diff --git a/src/Orleans.Runtime/Catalog/ActivationCollector.cs b/src/Orleans.Runtime/Catalog/ActivationCollector.cs
index ef7144a4efe..9cab47c93a2 100644
--- a/src/Orleans.Runtime/Catalog/ActivationCollector.cs
+++ b/src/Orleans.Runtime/Catalog/ActivationCollector.cs
@@ -103,7 +103,7 @@ public int GetNumRecentlyUsed(TimeSpan recencyPeriod)
         /// </param>
         public void ScheduleCollection(ICollectibleGrainContext item, TimeSpan timeout, DateTime now)
         {
-            lock (item)
+            lock (ActivationData.GetSynchronizationLock(item))
             {
                 if (item.IsExemptFromCollection)
                 {
@@ -131,7 +131,7 @@ public bool TryCancelCollection(ICollectibleGrainContext item)
             if (item is null) return false;
             if (item.IsExemptFromCollection) return false;
 
-            lock (item)
+            lock (ActivationData.GetSynchronizationLock(item))
             {
                 DateTime ticket = item.CollectionTicket;
                 if (default == ticket) return false;
@@ -154,7 +154,7 @@ public bool TryRescheduleCollection(ICollectibleGrainContext item)
         {
             if (item.IsExemptFromCollection) return false;
 
-            lock (item)
+            lock (ActivationData.GetSynchronizationLock(item))
             {
                 if (TryRescheduleCollection_Impl(item, item.CollectionAgeLimit)) return true;
 
@@ -236,7 +236,7 @@ public List<ICollectibleGrainContext> ScanStale()
                 // If the activation is to be reactivated, it's our job to clear the activation's copy of the ticket.
                 foreach (var activation in activations)
                 {
-                    lock (activation)
+                    lock (ActivationData.GetSynchronizationLock(activation))
                     {
                         activation.CollectionTicket = default;
                         if (!activation.IsValid)
@@ -283,7 +283,7 @@ public List<ICollectibleGrainContext> ScanAll(TimeSpan ageLimit)
                 foreach (var kvp in bucket.Items)
                 {
                     var activation = kvp.Value;
-                    lock (activation)
+                    lock (ActivationData.GetSynchronizationLock(activation))
                     {
                         if (!activation.IsValid)
                         {
@@ -691,7 +691,7 @@ public void Add(ICollectibleGrainContext item)
 
             public bool TryRemove(ICollectibleGrainContext item)
             {
-                lock (item)
+                lock (ActivationData.GetSynchronizationLock(item))
                 {
                     if (item.CollectionTicket == default)
                     {
@@ -711,7 +711,7 @@ public List<ICollectibleGrainContext> CancelAll()
                 {
                     // Attempt to cancel the item. if we succeed, it wasn't already cancelled and we can return it. otherwise, we silently ignore it.
                     var item = pair.Value;
-                    lock (item)
+                    lock (ActivationData.GetSynchronizationLock(item))
                     {
                         if (item.CollectionTicket == default)
                         {
diff --git a/src/Orleans.Runtime/Catalog/ActivationData.cs b/src/Orleans.Runtime/Catalog/ActivationData.cs
index 02e7fa5a40b..7e44b43bb26 100644
--- a/src/Orleans.Runtime/Catalog/ActivationData.cs
+++ b/src/Orleans.Runtime/Catalog/ActivationData.cs
@@ -22,8 +22,7 @@ namespace Orleans.Runtime;
 
 /// <summary>
 /// Maintains additional per-activation state that is required for Orleans internal operations.
-/// MUST lock this object for any concurrent access
-/// MUST lock on `this` object because there are locks taken on ActivationData instances in various places in the codebase such as ActivationCollector.ScheduleCollection.
+/// MUST use the activation synchronization lock for any concurrent access.
 /// Consider: compartmentalize by usage, e.g., using separate interfaces for data for catalog, etc.
 /// </summary>
 [DebuggerDisplay("GrainId = {GrainId}, State = {State}, Waiting = {WaitingCount}, Executing = {IsCurrentlyExecuting}")]
@@ -40,6 +39,7 @@ internal sealed partial class ActivationData :
     IDisposable
 {
     private const string GrainAddressMigrationContextKey = "sys.addr";
+    private readonly object _lock = new();
     private readonly GrainTypeSharedContext _shared;
     private readonly IServiceScope _serviceScope;
     private readonly WorkItemGroup _workItemGroup;
@@ -118,8 +118,8 @@ internal void SetActivationActivity(Activity activity)
     public void Start(IGrainActivator grainActivator)
     {
         Debug.Assert(Equals(ActivationTaskScheduler, TaskScheduler.Current));
-        // locking on `this` is intentional as there are other places in the codebase taking locks on ActivationData instances
-        lock (this)
+        // The activation synchronization lock protects mutable activation state.
+        lock (_lock)
         {
             try
             {
@@ -148,6 +148,7 @@ public void Start(IGrainActivator grainActivator)
     public ActivationState State { get; private set; } = ActivationState.Creating;
     public PlacementStrategy PlacementStrategy => _shared.PlacementStrategy;
     public DateTime CollectionTicket { get; set; }
+    internal object SynchronizationLock => _lock;
     public IServiceProvider ActivationServices => _serviceScope.ServiceProvider;
     public ActivationId ActivationId => Address.ActivationId;
     public IGrainLifecycle ObservableLifecycle
@@ -155,12 +156,15 @@ public IGrainLifecycle ObservableLifecycle
         get
         {
             if (_lifecycle is { } lifecycle) return lifecycle;
-            lock (this) { return _lifecycle ??= new GrainLifecycle(_shared.Logger); }
+            lock (_lock) { return _lifecycle ??= new GrainLifecycle(_shared.Logger); }
         }
     }
 
     internal GrainTypeSharedContext Shared => _shared;
 
+    internal static object GetSynchronizationLock(ICollectibleGrainContext context) =>
+        context is ActivationData activation ? activation._lock : context;
+
     public GrainId GrainId => Address.GrainId;
     public bool IsExemptFromCollection => _shared.CollectionAgeLimit == Timeout.InfiniteTimeSpan;
     public DateTime KeepAliveUntil { get; set; } = DateTime.MinValue;
@@ -186,7 +190,7 @@ public SiloAddress? ForwardingAddress
         get => _extras?.ForwardingAddress;
         set
         {
-            lock (this)
+            lock (_lock)
             {
                 _extras ??= new();
                 _extras.ForwardingAddress = value;
@@ -203,7 +207,7 @@ public GrainAddress? PreviousRegistration
         get => _extras?.PreviousRegistration;
         set
         {
-            lock (this)
+            lock (_lock)
             {
                 _extras ??= new();
                 _extras.PreviousRegistration = value;
@@ -218,7 +222,7 @@ private DeactivationReason DeactivationReason
         get => _extras?.DeactivationReason ?? default;
         set
         {
-            lock (this)
+            lock (_lock)
             {
                 _extras ??= new();
                 _extras.DeactivationReason = value;
@@ -231,7 +235,7 @@ private HashSet<IGrainTimer>? Timers
         get => _extras?.Timers;
         set
         {
-            lock (this)
+            lock (_lock)
             {
                 _extras ??= new();
                 _extras.Timers = value;
@@ -244,7 +248,7 @@ private DateTime? DeactivationStartTime
         get => _extras?.DeactivationStartTime;
         set
         {
-            lock (this)
+            lock (_lock)
             {
                 _extras ??= new();
                 _extras.DeactivationStartTime = value;
@@ -257,7 +261,7 @@ private bool IsStuckDeactivating
         get => _extras?.IsStuckDeactivating ?? false;
         set
         {
-            lock (this)
+            lock (_lock)
             {
                 _extras ??= new();
                 _extras.IsStuckDeactivating = value;
@@ -270,7 +274,7 @@ private bool IsStuckProcessingMessage
         get => _extras?.IsStuckProcessingMessage ?? false;
         set
         {
-            lock (this)
+            lock (_lock)
             {
                 _extras ??= new();
                 _extras.IsStuckProcessingMessage = value;
@@ -283,7 +287,7 @@ private DehydrationContextHolder? DehydrationContext
         get => _extras?.DehydrationContext;
         set
         {
-            lock (this)
+            lock (_lock)
             {
                 _extras ??= new();
                 _extras.DehydrationContext = value;
@@ -360,7 +364,7 @@ public void SetComponent(Type componentType, object? instance)
             throw new ArgumentException("Cannot override a component which is implemented by this grain context");
         }
 
-        lock (this)
+        lock (_lock)
         {
             if (instance == null)
             {
@@ -377,7 +381,7 @@ internal void SetGrainInstance(object grainInstance)
     {
         ArgumentNullException.ThrowIfNull(grainInstance);
 
-        lock (this)
+        lock (_lock)
         {
             if (GrainInstance is not null)
             {
@@ -444,7 +448,7 @@ public void SetState(ActivationState state)
 
     internal int GetRequestCount()
     {
-        lock (this)
+        lock (_lock)
         {
             return _runningRequests.Count + WaitingCount;
         }
@@ -452,7 +456,7 @@ internal int GetRequestCount()
 
     internal List<Message> DequeueAllWaitingRequests()
     {
-        lock (this)
+        lock (_lock)
         {
             var result = new List<Message>(_waitingRequests.Count);
             foreach (var (message, _) in _waitingRequests)
@@ -510,7 +514,7 @@ public void DelayDeactivation(TimeSpan timespan)
 
     private void ScheduleOperation(object operation)
     {
-        lock (this)
+        lock (_lock)
         {
             _pendingOperations ??= new();
             _pendingOperations.Enqueue(operation);
@@ -521,7 +525,7 @@ private void ScheduleOperation(object operation)
 
     private void CancelPendingOperations()
     {
-        lock (this)
+        lock (_lock)
         {
             // If the grain is currently activating, cancel that operation.
             if (_pendingOperations is not { Count: > 0 } operations)
@@ -569,7 +573,7 @@ private void CancelPendingOperations()
 
     public void Migrate(Dictionary<string, object>? requestContext, CancellationToken cancellationToken = default)
     {
-        lock (this)
+        lock (_lock)
         {
             if (State is not (ActivationState.Activating or ActivationState.Valid or ActivationState.Deactivating))
             {
@@ -595,7 +599,7 @@ public void Deactivate(DeactivationReason reason, ActivityContext? activityConte
             ? ActivitySources.LifecycleGrainSource.StartActivity(ActivityNames.DeactivateGrain, ActivityKind.Internal, parentContext:parent)
             : ActivitySources.LifecycleGrainSource.StartActivity(ActivityNames.DeactivateGrain);
         
-        lock (this)
+        lock (_lock)
         {
             try
             {
@@ -677,7 +681,7 @@ private void DeactivateStuckActivation()
 
     void IGrainTimerRegistry.OnTimerCreated(IGrainTimer timer)
     {
-        lock (this)
+        lock (_lock)
         {
             Timers ??= new HashSet<IGrainTimer>();
             Timers.Add(timer);
@@ -686,7 +690,7 @@ void IGrainTimerRegistry.OnTimerCreated(IGrainTimer timer)
 
     void IGrainTimerRegistry.OnTimerDisposed(IGrainTimer timer)
     {
-        lock (this) // need to lock since dispose can be called on finalizer thread, outside grain context (not single threaded).
+        lock (_lock) // need to lock since dispose can be called on finalizer thread, outside grain context (not single threaded).
         {
             if (Timers is null)
             {
@@ -699,7 +703,7 @@ void IGrainTimerRegistry.OnTimerDisposed(IGrainTimer timer)
 
     private void DisposeTimers()
     {
-        lock (this)
+        lock (_lock)
         {
             if (Timers is null)
             {
@@ -724,7 +728,7 @@ public void AnalyzeWorkload(DateTime now, IMessageCenter messageCenter, MessageF
         var longQueueTimeDuration = options.RequestQueueDelayWarningTime;
 
         List<string>? diagnostics = null;
-        lock (this)
+        lock (_lock)
         {
             if (State != ActivationState.Valid)
             {
@@ -826,7 +830,7 @@ void GetStatusList([NotNull] ref List<string>? diagnostics)
 
     internal string ToDetailedString(bool includeExtraDetails = false)
     {
-        lock (this)
+        lock (_lock)
         {
             var currentlyExecuting = includeExtraDetails ? _blockingRequest : null;
             return @$"[Activation: {Address.SiloAddress}/{GrainId}{ActivationId} {GetActivationInfoString()} State={State} NonReentrancyQueueSize={WaitingCount} NumRunning={_runningRequests.Count} IdlenessTimeSpan={GetIdleness()} CollectionAgeLimit={_shared.CollectionAgeLimit}{(currentlyExecuting != null ? " CurrentlyExecuting=" : null)}{currentlyExecuting}]";
@@ -859,7 +863,7 @@ public async ValueTask DisposeAsync()
 
         CancelPendingOperations();
 
-        lock (this)
+        lock (_lock)
         {
             _shared.InternalRuntime.ActivationWorkingSet.OnDeactivated(this);
             SetState(ActivationState.Invalid);
@@ -959,7 +963,7 @@ public TExtensionInterface GetExtension<TExtensionInterface>()
     bool IActivationWorkingSetMember.IsCandidateForRemoval(bool wouldRemove)
     {
         const int IdlenessLowerBound = 10_000;
-        lock (this)
+        lock (_lock)
         {
             var inactive = IsInactive && _idleDuration.ElapsedMilliseconds > IdlenessLowerBound;
 
@@ -986,7 +990,7 @@ private async Task RunMessageLoop()
                 if (!IsCurrentlyExecuting)
                 {
                     bool hasPendingOperations;
-                    lock (this)
+                    lock (_lock)
                     {
                         hasPendingOperations = _pendingOperations is { Count: > 0 };
                     }
@@ -1014,7 +1018,7 @@ void ProcessPendingRequests()
             do
             {
                 Message? message = null;
-                lock (this)
+                lock (_lock)
                 {
                     if (_waitingRequests.Count <= i)
                     {
@@ -1229,7 +1233,7 @@ async Task ProcessOperationsAsync()
             object? op = null;
             while (true)
             {
-                lock (this)
+                lock (_lock)
                 {
                     Debug.Assert(_pendingOperations is not null);
 
@@ -1307,7 +1311,7 @@ private void RehydrateInternal(IRehydrationContext context)
                 rehydrateSpan?.SetTag(ActivityTagKeys.ActivationId, ActivationId.ToString());
             }
 
-            lock (this)
+            lock (_lock)
             {
                 if (State != ActivationState.Creating)
                 {
@@ -1355,7 +1359,7 @@ private void OnDehydrate(IDehydrationContext context)
     {
         LogDehydratingActivation(_shared.Logger);
 
-        lock (this)
+        lock (_lock)
         {
             Debug.Assert(context is not null);
 
@@ -1469,7 +1473,7 @@ static async ValueTask OnCompleteAsync(ActivationData activation, Message messag
     /// <param name="message">The message that has just completed processing.</param>
     private void OnCompletedRequest(Message message)
     {
-        lock (this)
+        lock (_lock)
         {
             _runningRequests.Remove(message);
 
@@ -1523,7 +1527,7 @@ public void ReceiveMessage(Message message)
 
     private void ReceiveResponse(Message message)
     {
-        lock (this)
+        lock (_lock)
         {
             if (State == ActivationState.Invalid)
             {
@@ -1549,7 +1553,7 @@ private void ReceiveRequest(Message message)
             return;
         }
 
-        lock (this)
+        lock (_lock)
         {
             _waitingRequests.Add((message, CoarseStopwatch.StartNew()));
         }
@@ -1562,7 +1566,7 @@ private void ReceiveRequest(Message message)
     /// </summary>
     private void RejectAllQueuedMessages()
     {
-        lock (this)
+        lock (_lock)
         {
             List<Message> msgs = DequeueAllWaitingRequests();
             if (msgs == null || msgs.Count <= 0) return;
@@ -1581,7 +1585,7 @@ private void RejectAllQueuedMessages()
 
     private void RerouteAllQueuedMessages()
     {
-        lock (this)
+        lock (_lock)
         {
             List<Message> msgs = DequeueAllWaitingRequests();
             if (msgs is not { Count: > 0 })
@@ -1745,7 +1749,7 @@ private async Task ActivateAsync(Dictionary<string, object>? requestContextData,
                 }
             }
 
-            lock (this)
+            lock (_lock)
             {
                 SetState(ActivationState.Activating);
             }
@@ -1827,7 +1831,7 @@ private async Task ActivateAsync(Dictionary<string, object>? requestContextData,
                     }
                 }
 
-                lock (this)
+                lock (_lock)
                 {
                     if (State is ActivationState.Activating)
                     {
@@ -2082,7 +2086,7 @@ async ValueTask<bool> StartMigrationAsync(DehydrationContextHolder context, IAct
 
     private TaskCompletionSource<bool> GetDeactivationCompletionSource()
     {
-        lock (this)
+        lock (_lock)
         {
             _extras ??= new();
             return _extras.DeactivationTask ??= new TaskCompletionSource<bool>(TaskCreationOptions.RunContinuationsAsynchronously);
@@ -2210,7 +2214,7 @@ bool TryCancelRequest()
         {
             Message? message = null;
             var wasWaiting = false;
-            lock (this)
+            lock (_lock)
             {
                 // Check the running requests.
                 foreach (var candidate in _runningRequests.Keys)
@@ -2369,12 +2373,13 @@ private sealed class DeactivationInfo
     private abstract class Command(CancellationTokenSource cts) : IDisposable
     {
         private bool _disposed;
+        private readonly object _lock = new();
         private readonly CancellationTokenSource _cts = cts;
         public CancellationToken CancellationToken => _cts.Token;
 
         public virtual void Cancel()
         {
-            lock (this)
+            lock (_lock)
             {
                 if (_disposed) return;
                 _cts.Cancel();
@@ -2385,7 +2390,7 @@ public virtual void Dispose()
         {
             try
             {
-                lock (this)
+                lock (_lock)
                 {
                     _disposed = true;
                     _cts.Dispose();
diff --git a/src/Orleans.Runtime/Catalog/ActivationMigrationManager.cs b/src/Orleans.Runtime/Catalog/ActivationMigrationManager.cs
index bdf350554f5..5a0072e33af 100644
--- a/src/Orleans.Runtime/Catalog/ActivationMigrationManager.cs
+++ b/src/Orleans.Runtime/Catalog/ActivationMigrationManager.cs
@@ -126,7 +126,7 @@ public async ValueTask AcceptMigratingGrains(List<GrainMigrationPackage> migrati
             var allActiveOrTerminal = true;
             foreach (var activation in activations)
             {
-                lock (activation)
+                lock (activation.SynchronizationLock)
                 {
                     if (activation.State is not (ActivationState.Valid or ActivationState.Invalid))
                     {
diff --git a/src/Orleans.Runtime/Catalog/IncomingRequestMonitor.cs b/src/Orleans.Runtime/Catalog/IncomingRequestMonitor.cs
index df296736ab1..16dc5dcb075 100644
--- a/src/Orleans.Runtime/Catalog/IncomingRequestMonitor.cs
+++ b/src/Orleans.Runtime/Catalog/IncomingRequestMonitor.cs
@@ -123,7 +123,7 @@ private async Task Run()
                 foreach (var activationEntry in _recentlyUsedActivations)
                 {
                     var activation = activationEntry.Key;
-                    lock (activation)
+                    lock (activation.SynchronizationLock)
                     {
                         activation.AnalyzeWorkload(now, messageCenter, _messageFactory, options);
                     }