diff --git a/src/event/quic/ngx_event_quic_ack.c b/src/event/quic/ngx_event_quic_ack.c
index abd3f7ade..aae314658 100644
--- a/src/event/quic/ngx_event_quic_ack.c
+++ b/src/event/quic/ngx_event_quic_ack.c
@@ -827,6 +827,12 @@ ngx_quic_resend_frames(ngx_connection_t *c, ngx_quic_send_ctx_t *ctx)
             ngx_quic_queue_frame(qc, f);
             break;
 
+        case NGX_QUIC_FT_DATA_BLOCKED:
+            if (qc->streams.send_max_data == f->u.data_blocked.limit) {
+                ngx_queue_insert_tail(&ctx->frames, &f->queue);
+            }
+            break;
+
         case NGX_QUIC_FT_STREAM:
             qs = ngx_quic_find_stream(&qc->streams.tree, f->u.stream.stream_id);
 
diff --git a/src/event/quic/ngx_event_quic_connection.h b/src/event/quic/ngx_event_quic_connection.h
index 33922cf80..ad5025519 100644
--- a/src/event/quic/ngx_event_quic_connection.h
+++ b/src/event/quic/ngx_event_quic_connection.h
@@ -166,8 +166,8 @@ typedef struct {
     uint64_t                          client_streams_uni;
     uint64_t                          client_streams_bidi;
 
-    ngx_uint_t                        initialized;
-                                                 /* unsigned  initialized:1; */
+    unsigned                          initialized:1;
+    unsigned                          flow_control_blocked:1;
 } ngx_quic_streams_t;
 
 
diff --git a/src/event/quic/ngx_event_quic_streams.c b/src/event/quic/ngx_event_quic_streams.c
index 18fffeabe..26637e8fb 100644
--- a/src/event/quic/ngx_event_quic_streams.c
+++ b/src/event/quic/ngx_event_quic_streams.c
@@ -1054,6 +1054,30 @@ ngx_quic_stream_flush(ngx_quic_stream_t *qs)
     }
 
     if (len == 0 && !last) {
+        /*
+         * RFC 9000, 4.1. Data Flow Control
+         *
+         * A sender SHOULD send a STREAM_DATA_BLOCKED or DATA_BLOCKED frame to
+         * indicate to the receiver that it has data to write but is blocked by
+         * flow control limits.
+         */
+        if (qc->streams.send_max_data == qc->streams.send_offset
+            && !qc->streams.flow_control_blocked)
+        {
+            qc->streams.flow_control_blocked = 1;
+
+            frame = ngx_quic_alloc_frame(pc);
+            if (frame == NULL) {
+                return NGX_ERROR;
+            }
+
+            frame->level = ssl_encryption_application;
+            frame->type = NGX_QUIC_FT_DATA_BLOCKED;
+            frame->u.data_blocked.limit = qc->streams.send_max_data;
+
+            ngx_quic_queue_frame(qc, frame);
+        }
+
         return NGX_OK;
     }
 
@@ -1344,6 +1368,8 @@ ngx_quic_handle_max_data_frame(ngx_connection_t *c,
     }
 
     qc->streams.send_max_data = f->max_data;
+    qc->streams.flow_control_blocked = 0;
+
     node = ngx_rbtree_min(tree->root, tree->sentinel);
 
     while (node && qc->streams.send_offset < qc->streams.send_max_data) {
diff --git a/src/event/quic/ngx_event_quic_transport.c b/src/event/quic/ngx_event_quic_transport.c
index ba6211c33..ddbdea47d 100644
--- a/src/event/quic/ngx_event_quic_transport.c
+++ b/src/event/quic/ngx_event_quic_transport.c
@@ -118,6 +118,8 @@ static size_t ngx_quic_create_max_stream_data(u_char *p,
     ngx_quic_max_stream_data_frame_t *ms);
 static size_t ngx_quic_create_max_data(u_char *p,
     ngx_quic_max_data_frame_t *md);
+static size_t ngx_quic_create_data_blocked(u_char *p,
+    ngx_quic_data_blocked_frame_t *db);
 static size_t ngx_quic_create_path_challenge(u_char *p,
     ngx_quic_path_challenge_frame_t *pc);
 static size_t ngx_quic_create_path_response(u_char *p,
@@ -1328,6 +1330,9 @@ ngx_quic_create_frame(u_char *p, ngx_quic_frame_t *f)
     case NGX_QUIC_FT_MAX_DATA:
         return ngx_quic_create_max_data(p, &f->u.max_data);
 
+    case NGX_QUIC_FT_DATA_BLOCKED:
+        return ngx_quic_create_data_blocked(p, &f->u.data_blocked);
+
     case NGX_QUIC_FT_PATH_CHALLENGE:
         return ngx_quic_create_path_challenge(p, &f->u.path_challenge);
 
@@ -1889,6 +1894,27 @@ ngx_quic_create_max_data(u_char *p, ngx_quic_max_data_frame_t *md)
 }
 
 
+static size_t
+ngx_quic_create_data_blocked(u_char *p, ngx_quic_data_blocked_frame_t *db)
+{
+    size_t   len;
+    u_char  *start;
+
+    if (p == NULL) {
+        len = ngx_quic_varint_len(NGX_QUIC_FT_DATA_BLOCKED);
+        len += ngx_quic_varint_len(db->limit);
+        return len;
+    }
+
+    start = p;
+
+    ngx_quic_build_int(&p, NGX_QUIC_FT_DATA_BLOCKED);
+    ngx_quic_build_int(&p, db->limit);
+
+    return p - start;
+}
+
+
 static size_t
 ngx_quic_create_path_challenge(u_char *p, ngx_quic_path_challenge_frame_t *pc)
 {