diff --git a/src/include/dawn_wire/WireClient.h b/src/include/dawn_wire/WireClient.h
index b2fd8d569f..f35803593a 100644
--- a/src/include/dawn_wire/WireClient.h
+++ b/src/include/dawn_wire/WireClient.h
@@ -74,7 +74,7 @@ namespace dawn_wire {
             virtual ReadHandle* CreateReadHandle(DawnBuffer, uint64_t offset, size_t size);
             virtual WriteHandle* CreateWriteHandle(DawnBuffer, uint64_t offset, size_t size);
 
-            class ReadHandle {
+            class DAWN_WIRE_EXPORT ReadHandle {
               public:
                 // Serialize the handle into |serializePointer| so it can be received by the server.
                 // If |serializePointer| is nullptr, this returns the required serialization space.
@@ -93,7 +93,7 @@ namespace dawn_wire {
                 virtual ~ReadHandle();
             };
 
-            class WriteHandle {
+            class DAWN_WIRE_EXPORT WriteHandle {
               public:
                 // Serialize the handle into |serializePointer| so it can be received by the server.
                 // If |serializePointer| is nullptr, this returns the required serialization space.
diff --git a/src/include/dawn_wire/WireServer.h b/src/include/dawn_wire/WireServer.h
index 5ebe4b1bcd..9c3da94a81 100644
--- a/src/include/dawn_wire/WireServer.h
+++ b/src/include/dawn_wire/WireServer.h
@@ -63,7 +63,7 @@ namespace dawn_wire {
                                                 size_t deserializeSize,
                                                 WriteHandle** writeHandle) = 0;
 
-            class ReadHandle {
+            class DAWN_WIRE_EXPORT ReadHandle {
               public:
                 // Initialize the handle data.
                 // Serialize into |serializePointer| so the client can update handle data.
@@ -74,7 +74,7 @@ namespace dawn_wire {
                 virtual ~ReadHandle();
             };
 
-            class WriteHandle {
+            class DAWN_WIRE_EXPORT WriteHandle {
               public:
                 // Set the target for writes from the client. DeserializeFlush should copy data
                 // into the target.