diff --git a/src/script.c b/src/script.c
index 68a5d081..dae0e95e 100644
--- a/src/script.c
+++ b/src/script.c
@@ -164,7 +164,7 @@ void script_request(lua_State *L, char **buf, size_t *len) {
     lua_pop(L, pop);
 }
 
-void script_response(lua_State *L, int status, buffer *headers, buffer *body) {
+void script_response(lua_State *L, int status, buffer *headers, buffer *body, uint64_t req_latency) {
     lua_getglobal(L, "response");
     lua_pushinteger(L, status);
     lua_newtable(L);
@@ -176,7 +176,8 @@ void script_response(lua_State *L, int status, buffer *headers, buffer *body) {
     }
 
     lua_pushlstring(L, body->buffer, body->cursor - body->buffer);
-    lua_call(L, 3, 0);
+    lua_pushnumber(L, req_latency);
+    lua_call(L, 4, 0);
 
     buffer_reset(headers);
     buffer_reset(body);
diff --git a/src/script.h b/src/script.h
index 1bf820da..3dc64ead 100644
--- a/src/script.h
+++ b/src/script.h
@@ -18,7 +18,7 @@ void script_done(lua_State *, stats *, stats *);
 void script_init(lua_State *, thread *, int, char **);
 uint64_t script_delay(lua_State *);
 void script_request(lua_State *, char **, size_t *);
-void script_response(lua_State *, int, buffer *, buffer *);
+void script_response(lua_State *, int, buffer *, buffer *, uint64_t);
 size_t script_verify_request(lua_State *L);
 
 bool script_is_static(lua_State *);
diff --git a/src/wrk.c b/src/wrk.c
index 51f46f72..7e56e486 100644
--- a/src/wrk.c
+++ b/src/wrk.c
@@ -336,7 +336,7 @@ static int response_complete(http_parser *parser) {
 
     if (c->headers.buffer) {
         *c->headers.cursor++ = '\0';
-        script_response(thread->L, status, &c->headers, &c->body);
+        script_response(thread->L, status, &c->headers, &c->body, now - c->start);
         c->state = FIELD;
     }