diff --git a/ChangeLog.adoc b/ChangeLog.adoc
index 7948ab635..2f5bd97a4 100644
--- a/ChangeLog.adoc
+++ b/ChangeLog.adoc
@@ -52,6 +52,7 @@ Bug fixes::
   * irc: fix buffer switching on manual join for forwarded channels (issue #876)
   * irc: add missing tags on CTCP message sent
   * lua: fix integers returned in Lua >= 5.3 (issue #834)
+  * relay: make HTTP headers case-insensitive for WebSocket connections (issue #888)
   * relay: set status to "authentication failed" and close immediately connection in case of authentication failure in weechat and irc protocols (issue #825)
   * script: reload a script after upgrade only if it was loaded, set autoload only if the script was auto-loaded (issue #855)
 
diff --git a/src/plugins/relay/relay-client.c b/src/plugins/relay/relay-client.c
index 7a1c4adf0..be4b40786 100644
--- a/src/plugins/relay/relay-client.c
+++ b/src/plugins/relay/relay-client.c
@@ -411,7 +411,7 @@ relay_client_recv_text (struct t_relay_client *client, const char *data)
                                             weechat_prefix ("error"),
                                             RELAY_PLUGIN_NAME,
                                             weechat_hashtable_get (client->http_headers,
-                                                                   "Origin"));
+                                                                   "origin"));
                                     }
                                     break;
                             }
@@ -419,7 +419,7 @@ relay_client_recv_text (struct t_relay_client *client, const char *data)
                         }
 
                         ptr_real_ip = weechat_hashtable_get (
-                            client->http_headers, "X-Real-IP");
+                            client->http_headers, "x-real-ip");
                         if (ptr_real_ip)
                         {
                             weechat_printf_date_tags (
diff --git a/src/plugins/relay/relay-websocket.c b/src/plugins/relay/relay-websocket.c
index 8712a2a7d..b650f8442 100644
--- a/src/plugins/relay/relay-websocket.c
+++ b/src/plugins/relay/relay-websocket.c
@@ -86,10 +86,11 @@ relay_websocket_save_header (struct t_relay_client *client,
     if (!pos || (pos == message))
         return;
 
-    /* get header name */
+    /* get header name, which is case-insensitive */
     name = weechat_strndup (message, pos - message);
     if (!name)
         return;
+    weechat_string_tolower (name);
 
     /* get pointer on header value */
     ptr_value = pos + 1;
@@ -143,20 +144,20 @@ relay_websocket_client_handshake_valid (struct t_relay_client *client)
     const char *value;
 
     /* check if we have header "Upgrade" with value "websocket" */
-    value = weechat_hashtable_get (client->http_headers, "Upgrade");
+    value = weechat_hashtable_get (client->http_headers, "upgrade");
     if (!value)
         return -1;
     if (weechat_strcasecmp (value, "websocket") != 0)
         return -1;
 
     /* check if we have header "Sec-WebSocket-Key" with non-empty value */
-    value = weechat_hashtable_get (client->http_headers, "Sec-WebSocket-Key");
+    value = weechat_hashtable_get (client->http_headers, "sec-websocket-key");
     if (!value || !value[0])
         return -1;
 
     if (relay_config_regex_websocket_allowed_origins)
     {
-        value = weechat_hashtable_get (client->http_headers, "Origin");
+        value = weechat_hashtable_get (client->http_headers, "origin");
         if (!value || !value[0])
             return -2;
         if (regexec (relay_config_regex_websocket_allowed_origins, value, 0,
@@ -193,7 +194,7 @@ relay_websocket_build_handshake (struct t_relay_client *client)
     int length;
 
     sec_websocket_key = weechat_hashtable_get (client->http_headers,
-                                               "Sec-WebSocket-Key");
+                                               "sec-websocket-key");
     if (!sec_websocket_key || !sec_websocket_key[0])
         return NULL;