diff --git a/rsocket-core/src/main/java/io/rsocket/core/RSocketRequester.java b/rsocket-core/src/main/java/io/rsocket/core/RSocketRequester.java
index b8a9c00ff..4e7b2c2c9 100644
--- a/rsocket-core/src/main/java/io/rsocket/core/RSocketRequester.java
+++ b/rsocket-core/src/main/java/io/rsocket/core/RSocketRequester.java
@@ -198,6 +198,7 @@ public void dispose() {
     }
 
     getDuplexConnection().sendErrorAndClose(new ConnectionErrorException("Disposed"));
+    tryTerminateAndCloseConnection(() -> new ConnectionErrorException("Disposed"));
   }
 
   @Override
@@ -308,10 +309,14 @@ private void handleMissingResponseProcessor(int streamId, FrameType type, ByteBu
   }
 
   private void tryTerminateOnKeepAlive(KeepAliveSupport.KeepAlive keepAlive) {
-    tryTerminate(
+    tryTerminateAndCloseConnection(
         () ->
             new ConnectionErrorException(
                 String.format("No keep-alive acks for %d ms", keepAlive.getTimeout().toMillis())));
+  }
+
+  private void tryTerminateAndCloseConnection(Supplier<Throwable> errorSupplier) {
+    tryTerminate(errorSupplier);
     getDuplexConnection().dispose();
   }
 
diff --git a/rsocket-core/src/test/java/io/rsocket/core/RSocketRequesterDisposeTest.java b/rsocket-core/src/test/java/io/rsocket/core/RSocketRequesterDisposeTest.java
new file mode 100644
index 000000000..4903d844f
--- /dev/null
+++ b/rsocket-core/src/test/java/io/rsocket/core/RSocketRequesterDisposeTest.java
@@ -0,0 +1,142 @@
+/*
+ * Copyright 2015-2026 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.rsocket.core;
+
+import static io.rsocket.frame.FrameLengthCodec.FRAME_LENGTH_MASK;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.ByteBufAllocator;
+import io.rsocket.Payload;
+import io.rsocket.RSocketErrorException;
+import io.rsocket.buffer.LeaksTrackingByteBufAllocator;
+import io.rsocket.exceptions.ConnectionErrorException;
+import io.rsocket.frame.ErrorFrameCodec;
+import io.rsocket.frame.FrameHeaderCodec;
+import io.rsocket.frame.FrameType;
+import io.rsocket.frame.decoder.PayloadDecoder;
+import io.rsocket.test.util.TestDuplexConnection;
+import io.rsocket.util.EmptyPayload;
+import java.time.Duration;
+import io.netty.util.ReferenceCountUtil;
+import org.assertj.core.api.Assertions;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.Test;
+import reactor.core.publisher.Sinks;
+import reactor.test.StepVerifier;
+
+/** Regression tests for https://github.com/rsocket/rsocket-java/issues/1126 */
+class RSocketRequesterDisposeTest {
+
+  private final LeaksTrackingByteBufAllocator allocator =
+      LeaksTrackingByteBufAllocator.instrument(ByteBufAllocator.DEFAULT);
+
+  private NettyLikeDuplexConnection connection;
+  private Sinks.Empty<Void> requesterClosedSink;
+  private RSocketRequester requester;
+
+  @AfterEach
+  void tearDown() {
+    if (connection != null) {
+      connection.getSent().forEach(ReferenceCountUtil::safeRelease);
+      connection.clearSendReceiveBuffers();
+      allocator.assertHasNoLeaks();
+    }
+  }
+
+  @Test
+  void disposeTerminatesRequesterWhenSendErrorAndCloseDoesNotCloseConnection() {
+    connection = new NettyLikeDuplexConnection(allocator);
+    requesterClosedSink = Sinks.empty();
+    requester =
+        new RSocketRequester(
+            connection,
+            PayloadDecoder.ZERO_COPY,
+            StreamIdSupplier.clientSupplier(),
+            0,
+            FRAME_LENGTH_MASK,
+            Integer.MAX_VALUE,
+            0,
+            0,
+            null,
+            __ -> null,
+            null,
+            requesterClosedSink,
+            requesterClosedSink.asMono());
+
+    StepVerifier.create(requester.onClose())
+        .then(requester::dispose)
+        .expectError(ConnectionErrorException.class)
+        .verify(Duration.ofSeconds(5));
+
+    Assertions.assertThat(requester.isDisposed()).isTrue();
+    Assertions.assertThat(connection.isDisposed()).isTrue();
+
+    Payload payload = EmptyPayload.INSTANCE;
+    StepVerifier.create(requester.requestResponse(payload))
+        .expectError(ConnectionErrorException.class)
+        .verify(Duration.ofSeconds(5));
+  }
+
+  @Test
+  void disposeSendsConnectionErrorBeforeClosing() {
+    connection = new NettyLikeDuplexConnection(allocator);
+    requesterClosedSink = Sinks.empty();
+    requester =
+        new RSocketRequester(
+            connection,
+            PayloadDecoder.ZERO_COPY,
+            StreamIdSupplier.clientSupplier(),
+            0,
+            FRAME_LENGTH_MASK,
+            Integer.MAX_VALUE,
+            0,
+            0,
+            null,
+            __ -> null,
+            null,
+            requesterClosedSink,
+            requesterClosedSink.asMono());
+
+    requester.dispose();
+
+    Assertions.assertThat(connection.getSent())
+        .hasSize(1)
+        .first()
+        .satisfies(
+            frame -> {
+              Assertions.assertThat(FrameHeaderCodec.frameType(frame)).isEqualTo(FrameType.ERROR);
+              frame.release();
+            });
+  }
+
+  /**
+   * Mirrors {@link io.rsocket.transport.netty.TcpDuplexConnection#sendErrorAndClose}: sends a
+   * connection error frame without completing {@link io.rsocket.DuplexConnection#onClose()}.
+   */
+  static final class NettyLikeDuplexConnection extends TestDuplexConnection {
+
+    NettyLikeDuplexConnection(LeaksTrackingByteBufAllocator allocator) {
+      super(allocator);
+    }
+
+    @Override
+    public void sendErrorAndClose(RSocketErrorException e) {
+      ByteBuf errorFrame = ErrorFrameCodec.encode(alloc(), 0, e);
+      sendFrame(0, errorFrame);
+    }
+  }
+}