diff --git a/src/h2.c b/src/h2.c
index 536240a6d..fa929aece 100644
--- a/src/h2.c
+++ b/src/h2.c
@@ -318,6 +318,7 @@ int h2_make_htx_request(struct http_hdr *list, struct htx *htx, unsigned int *ms
 	struct htx_sl *sl = NULL;
 	unsigned int sl_flags = 0;
 	const char *ctl;
+	struct ist v;
 
 	lck = ck = -1; // no cookie for now
 	fields = 0;
@@ -434,7 +435,15 @@ int h2_make_htx_request(struct http_hdr *list, struct htx *htx, unsigned int *ms
 			continue;
 		}
 
-		if (!htx_add_header(htx, list[idx].n, list[idx].v))
+		/* trim leading/trailing LWS as per RC9113#8.2.1 */
+		for (v = list[idx].v; v.len; v.len--) {
+			if (unlikely(HTTP_IS_LWS(*v.ptr)))
+				v.ptr++;
+			else if (!unlikely(HTTP_IS_LWS(v.ptr[v.len - 1])))
+				break;
+		}
+
+		if (!htx_add_header(htx, list[idx].n, v))
 			goto fail;
 	}
 
@@ -623,6 +632,7 @@ int h2_make_htx_response(struct http_hdr *list, struct htx *htx, unsigned int *m
 	struct htx_sl *sl = NULL;
 	unsigned int sl_flags = 0;
 	const char *ctl;
+	struct ist v;
 
 	fields = 0;
 	for (idx = 0; list[idx].n.len != 0; idx++) {
@@ -702,7 +712,15 @@ int h2_make_htx_response(struct http_hdr *list, struct htx *htx, unsigned int *m
 		    isteq(list[idx].n, ist("transfer-encoding")))
 			goto fail;
 
-		if (!htx_add_header(htx, list[idx].n, list[idx].v))
+		/* trim leading/trailing LWS as per RC9113#8.2.1 */
+		for (v = list[idx].v; v.len; v.len--) {
+			if (unlikely(HTTP_IS_LWS(*v.ptr)))
+				v.ptr++;
+			else if (!unlikely(HTTP_IS_LWS(v.ptr[v.len - 1])))
+				break;
+		}
+
+		if (!htx_add_header(htx, list[idx].n, v))
 			goto fail;
 	}
 
@@ -781,6 +799,7 @@ int h2_make_htx_response(struct http_hdr *list, struct htx *htx, unsigned int *m
 int h2_make_htx_trailers(struct http_hdr *list, struct htx *htx)
 {
 	const char *ctl;
+	struct ist v;
 	uint32_t idx;
 	int i;
 
@@ -816,7 +835,15 @@ int h2_make_htx_trailers(struct http_hdr *list, struct htx *htx)
 		if (unlikely(ctl) && http_header_has_forbidden_char(list[idx].v, ctl))
 			goto fail;
 
-		if (!htx_add_trailer(htx, list[idx].n, list[idx].v))
+		/* trim leading/trailing LWS as per RC9113#8.2.1 */
+		for (v = list[idx].v; v.len; v.len--) {
+			if (unlikely(HTTP_IS_LWS(*v.ptr)))
+				v.ptr++;
+			else if (!unlikely(HTTP_IS_LWS(v.ptr[v.len - 1])))
+				break;
+		}
+
+		if (!htx_add_trailer(htx, list[idx].n, v))
 			goto fail;
 	}
 
diff --git a/src/mux_h2.c b/src/mux_h2.c
index 0370d6a13..68ad3eb3d 100644
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -19,6 +19,7 @@
 #include <haproxy/hpack-dec.h>
 #include <haproxy/hpack-enc.h>
 #include <haproxy/hpack-tbl.h>
+#include <haproxy/http.h>
 #include <haproxy/http_htx.h>
 #include <haproxy/htx.h>
 #include <haproxy/istbuf.h>
@@ -1209,11 +1210,20 @@ static inline int h2_encode_header(struct buffer *buf, const struct ist hn, cons
 				   uint64_t mask, const struct ist trc_loc, const char *func,
 				   const struct h2c *h2c, const struct h2s *h2s)
 {
+	struct ist v;
 	int ret;
 
-	ret = hpack_encode_header(buf, hn, hv);
+	/* trim leading/trailing LWS as per RC9113#8.2.1 */
+	for (v = hv; v.len; v.len--) {
+		if (unlikely(HTTP_IS_LWS(*v.ptr)))
+			v.ptr++;
+		else if (!unlikely(HTTP_IS_LWS(v.ptr[v.len - 1])))
+			break;
+	}
+
+	ret = hpack_encode_header(buf, hn, v);
 	if (ret)
-		h2_trace_header(hn, hv, mask, trc_loc, func, h2c, h2s);
+		h2_trace_header(hn, v, mask, trc_loc, func, h2c, h2s);
 
 	return ret;
 }