diff --git a/Sources/GRPCNIOTransportCore/Client/GRPCClientStreamHandler.swift b/Sources/GRPCNIOTransportCore/Client/GRPCClientStreamHandler.swift
index db9c43f..cdc8a60 100644
--- a/Sources/GRPCNIOTransportCore/Client/GRPCClientStreamHandler.swift
+++ b/Sources/GRPCNIOTransportCore/Client/GRPCClientStreamHandler.swift
@@ -29,6 +29,7 @@ final class GRPCClientStreamHandler: ChannelDuplexHandler {
 
   private var isReading = false
   private var flushPending = false
+  private var requestFinished = false
 
   init(
     methodDescriptor: MethodDescriptor,
@@ -263,6 +264,12 @@ extension GRPCClientStreamHandler {
           )
 
         case .noMoreMessages:
+          // If we're done writing (i.e. we have no more messages returned from state
+          // machine) then return.
+          if self.requestFinished { return }
+
+          self.requestFinished = true
+
           // Write an empty data frame with the EOS flag set, to signal the RPC
           // request is now finished.
           context.write(
@@ -276,7 +283,6 @@ extension GRPCClientStreamHandler {
             ),
             promise: nil
           )
-
           context.flush()
           break loop
 
diff --git a/Tests/GRPCNIOTransportCoreTests/Client/GRPCClientStreamHandlerTests.swift b/Tests/GRPCNIOTransportCoreTests/Client/GRPCClientStreamHandlerTests.swift
index b2c09c7..7f62f2e 100644
--- a/Tests/GRPCNIOTransportCoreTests/Client/GRPCClientStreamHandlerTests.swift
+++ b/Tests/GRPCNIOTransportCoreTests/Client/GRPCClientStreamHandlerTests.swift
@@ -529,14 +529,16 @@ final class GRPCClientStreamHandlerTests: XCTestCase {
     // Half-close the outbound end: this would be triggered by finishing the client's writer.
     XCTAssertNoThrow(channel.close(mode: .output, promise: nil))
 
-    // Flush to make sure the EOS is written.
-    channel.flush()
-
     // Make sure the EOS frame was sent
     let emptyEOSFrame = try channel.assertReadDataOutbound()
     XCTAssertEqual(emptyEOSFrame.data, .byteBuffer(.init()))
     XCTAssertTrue(emptyEOSFrame.endStream)
 
+    // Make sure that, if we flush again, we're not writing anything else down
+    // the stream. We should have closed at this point.
+    channel.flush()
+    XCTAssertNil(try channel.readOutbound(as: HTTP2Frame.FramePayload.self))
+
     // Make sure we cannot write anymore because client's closed.
     XCTAssertThrowsError(
       ofType: RPCError.self,