diff --git a/http3/response_writer.go b/http3/response_writer.go
index 2a45f586..0a42518c 100644
--- a/http3/response_writer.go
+++ b/http3/response_writer.go
@@ -57,7 +57,10 @@ func (w *responseWriter) WriteHeader(status int) {
 	if w.headerWritten {
 		return
 	}
-	w.headerWritten = true
+
+	if status < 100 || status >= 200 {
+		w.headerWritten = true
+	}
 	w.status = status
 
 	var headers bytes.Buffer
@@ -79,6 +82,9 @@ func (w *responseWriter) WriteHeader(status int) {
 	if _, err := w.bufferedStream.Write(headers.Bytes()); err != nil {
 		w.logger.Errorf("could not write header frame payload: %s", err.Error())
 	}
+	if !w.headerWritten {
+		w.Flush()
+	}
 }
 
 func (w *responseWriter) Write(p []byte) (int, error) {
diff --git a/http3/response_writer_test.go b/http3/response_writer_test.go
index 5b2cc2df..fb2ff186 100644
--- a/http3/response_writer_test.go
+++ b/http3/response_writer_test.go
@@ -24,7 +24,7 @@ var _ = Describe("Response Writer", func() {
 	BeforeEach(func() {
 		strBuf = &bytes.Buffer{}
 		str := mockquic.NewMockStream(mockCtrl)
-		str.EXPECT().Write(gomock.Any()).Do(strBuf.Write).AnyTimes()
+		str.EXPECT().Write(gomock.Any()).DoAndReturn(strBuf.Write).AnyTimes()
 		rw = newResponseWriter(str, utils.DefaultLogger)
 	})
 
@@ -117,6 +117,30 @@ var _ = Describe("Response Writer", func() {
 		Expect(fields).To(HaveKeyWithValue(":status", []string{"200"}))
 	})
 
+	It("allows calling WriteHeader() several times when using the 103 status code", func() {
+		rw.Header().Add("Link", "</style.css>; rel=preload; as=style")
+		rw.Header().Add("Link", "</script.js>; rel=preload; as=script")
+		rw.WriteHeader(http.StatusEarlyHints)
+
+		n, err := rw.Write([]byte("foobar"))
+		Expect(n).To(Equal(6))
+		Expect(err).ToNot(HaveOccurred())
+
+		// Early Hints must have been received
+		fields := decodeHeader(strBuf)
+		Expect(fields).To(HaveLen(2))
+		Expect(fields).To(HaveKeyWithValue(":status", []string{"103"}))
+		Expect(fields).To(HaveKeyWithValue("link", []string{"</style.css>; rel=preload; as=style", "</script.js>; rel=preload; as=script"}))
+
+		// According to the spec, headers sent in the informational response must also be included in the final response
+		fields = decodeHeader(strBuf)
+		Expect(fields).To(HaveLen(2))
+		Expect(fields).To(HaveKeyWithValue(":status", []string{"200"}))
+		Expect(fields).To(HaveKeyWithValue("link", []string{"</style.css>; rel=preload; as=style", "</script.js>; rel=preload; as=script"}))
+
+		Expect(getData(strBuf)).To(Equal([]byte("foobar")))
+	})
+
 	It("doesn't allow writes if the status code doesn't allow a body", func() {
 		rw.WriteHeader(304)
 		n, err := rw.Write([]byte("foobar"))