diff --git a/src/libraries/System.Runtime.InteropServices.JavaScript/src/System.Runtime.InteropServices.JavaScript.csproj b/src/libraries/System.Runtime.InteropServices.JavaScript/src/System.Runtime.InteropServices.JavaScript.csproj
index 353071ad0c5a0..e9c286f47aa84 100644
--- a/src/libraries/System.Runtime.InteropServices.JavaScript/src/System.Runtime.InteropServices.JavaScript.csproj
+++ b/src/libraries/System.Runtime.InteropServices.JavaScript/src/System.Runtime.InteropServices.JavaScript.csproj
@@ -5,6 +5,14 @@
     <Nullable>enable</Nullable>
   </PropertyGroup>
 
+   <PropertyGroup>
+     <FeatureWasmThreads Condition="'$(TargetOS)' == 'browser' and '$(WasmEnableThreads)' == 'true'">true</FeatureWasmThreads>
+   </PropertyGroup>
+
+   <PropertyGroup>
+       <DefineConstants Condition="'$(FeatureWasmThreads)' == 'true'" >$(DefineConstants);FEATURE_WASM_THREADS</DefineConstants>
+   </PropertyGroup>
+
   <!-- DesignTimeBuild requires all the TargetFramework Derived Properties to not be present in the first property group. -->
   <PropertyGroup>
     <TargetPlatformIdentifier>$([MSBuild]::GetTargetPlatformIdentifier('$(TargetFramework)'))</TargetPlatformIdentifier>
diff --git a/src/libraries/System.Runtime.InteropServices.JavaScript/src/System/Runtime/InteropServices/JavaScript/Interop/JavaScriptExports.cs b/src/libraries/System.Runtime.InteropServices.JavaScript/src/System/Runtime/InteropServices/JavaScript/Interop/JavaScriptExports.cs
index 3a884729fedfb..5b932edb7965d 100644
--- a/src/libraries/System.Runtime.InteropServices.JavaScript/src/System/Runtime/InteropServices/JavaScript/Interop/JavaScriptExports.cs
+++ b/src/libraries/System.Runtime.InteropServices.JavaScript/src/System/Runtime/InteropServices/JavaScript/Interop/JavaScriptExports.cs
@@ -195,6 +195,8 @@ public static void CompleteTask(JSMarshalerArgument* arguments_buffer)
             }
         }
 
+#if FEATURE_WASM_THREADS
+
         [MethodImpl(MethodImplOptions.NoInlining)] // https://github.com/dotnet/runtime/issues/71425
         // the marshaled signature is:
         // void InstallSynchronizationContext()
@@ -210,6 +212,8 @@ public static void InstallSynchronizationContext (JSMarshalerArgument* arguments
             }
         }
 
+#endif
+
         [MethodImpl(MethodImplOptions.NoInlining)] // https://github.com/dotnet/runtime/issues/71425
         public static void StopProfile()
         {
diff --git a/src/libraries/System.Runtime.InteropServices.JavaScript/src/System/Runtime/InteropServices/JavaScript/JSSynchronizationContext.cs b/src/libraries/System.Runtime.InteropServices.JavaScript/src/System/Runtime/InteropServices/JavaScript/JSSynchronizationContext.cs
index 9c87e4ec35140..47d14676d064f 100644
--- a/src/libraries/System.Runtime.InteropServices.JavaScript/src/System/Runtime/InteropServices/JavaScript/JSSynchronizationContext.cs
+++ b/src/libraries/System.Runtime.InteropServices.JavaScript/src/System/Runtime/InteropServices/JavaScript/JSSynchronizationContext.cs
@@ -1,6 +1,8 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+#if FEATURE_WASM_THREADS
+
 using System;
 using System.Threading;
 using System.Threading.Channels;
@@ -141,3 +143,5 @@ private void Pump () {
         }
     }
 }
+
+#endif
diff --git a/src/mono/wasm/runtime/managed-exports.ts b/src/mono/wasm/runtime/managed-exports.ts
index bbd48aa9e3014..09f6d9a33d024 100644
--- a/src/mono/wasm/runtime/managed-exports.ts
+++ b/src/mono/wasm/runtime/managed-exports.ts
@@ -22,8 +22,8 @@ export function init_managed_exports(): void {
     if (!runtimeHelpers.runtime_interop_exports_class)
         throw "Can't find " + runtimeHelpers.runtime_interop_namespace + "." + runtimeHelpers.runtime_interop_exports_classname + " class";
 
-    const install_sync_context = get_method("InstallSynchronizationContext");
-    mono_assert(install_sync_context, "Can't find InstallSynchronizationContext method");
+    const install_sync_context = cwraps.mono_wasm_assembly_find_method(runtimeHelpers.runtime_interop_exports_class, "InstallSynchronizationContext", -1);
+    // mono_assert(install_sync_context, "Can't find InstallSynchronizationContext method");
     const call_entry_point = get_method("CallEntrypoint");
     mono_assert(call_entry_point, "Can't find CallEntrypoint method");
     const release_js_owned_object_by_gc_handle_method = get_method("ReleaseJSOwnedObjectByGCHandle");
@@ -134,19 +134,22 @@ export function init_managed_exports(): void {
             anyModule.stackRestore(sp);
         }
     };
-    runtimeHelpers.javaScriptExports.install_synchronization_context = () => {
-        const sp = anyModule.stackSave();
-        try {
-            const args = alloc_stack_frame(2);
-            invoke_method_and_handle_exception(install_sync_context, args);
-        } finally {
-            anyModule.stackRestore(sp);
-        }
-    };
 
-    if (!ENVIRONMENT_IS_PTHREAD)
-        // Install our sync context so that async continuations will migrate back to this thread (the main thread) automatically
-        runtimeHelpers.javaScriptExports.install_synchronization_context();
+    if (install_sync_context) {
+        runtimeHelpers.javaScriptExports.install_synchronization_context = () => {
+            const sp = anyModule.stackSave();
+            try {
+                const args = alloc_stack_frame(2);
+                invoke_method_and_handle_exception(install_sync_context, args);
+            } finally {
+                anyModule.stackRestore(sp);
+            }
+        };
+
+        if (!ENVIRONMENT_IS_PTHREAD)
+            // Install our sync context so that async continuations will migrate back to this thread (the main thread) automatically
+            runtimeHelpers.javaScriptExports.install_synchronization_context();
+    }
 }
 
 export function get_method(method_name: string): MonoMethod {