diff --git a/spring-session/src/main/java/org/springframework/session/web/http/OnCommittedResponseWrapper.java b/spring-session/src/main/java/org/springframework/session/web/http/OnCommittedResponseWrapper.java
index a4dc830..304f7f6 100644
--- a/spring-session/src/main/java/org/springframework/session/web/http/OnCommittedResponseWrapper.java
+++ b/spring-session/src/main/java/org/springframework/session/web/http/OnCommittedResponseWrapper.java
@@ -187,7 +187,10 @@ abstract class OnCommittedResponseWrapper extends HttpServletResponseWrapper {
      */
     private void checkContentLength(long contentLengthToWrite) {
         contentWritten += contentLengthToWrite;
-        if(contentLength > 0  && contentWritten >= contentLength) {
+        boolean isBodyFullyWritten = contentLength > 0  && contentWritten >= contentLength;
+        int bufferSize = getBufferSize();
+        boolean requiresFlush = bufferSize > 0 && contentWritten >= bufferSize;
+        if(isBodyFullyWritten || requiresFlush) {
             doOnResponseCommitted();
         }
     }
diff --git a/spring-session/src/test/java/org/springframework/session/web/http/OnCommittedResponseWrapperTests.java b/spring-session/src/test/java/org/springframework/session/web/http/OnCommittedResponseWrapperTests.java
index 9d9fbae..88edc3d 100644
--- a/spring-session/src/test/java/org/springframework/session/web/http/OnCommittedResponseWrapperTests.java
+++ b/spring-session/src/test/java/org/springframework/session/web/http/OnCommittedResponseWrapperTests.java
@@ -1059,4 +1059,14 @@ public class OnCommittedResponseWrapperTests {
 
         assertThat(committed).isTrue();
     }
+
+    @Test
+    public void bufferSizePrintWriterWriteCommits() throws Exception {
+        String expected = "1234567890";
+        when(response.getBufferSize()).thenReturn(expected.length());
+
+        response.getWriter().write(expected);
+
+        assertThat(committed).isTrue();
+    }
 }
\ No newline at end of file