diff --git a/README.md b/README.md
index 97e05cfa..89af1c70 100644
--- a/README.md
+++ b/README.md
@@ -164,6 +164,7 @@ behavior.
 * [lua_ssl_certificate_key](https://github.com/openresty/lua-nginx-module#lua_ssl_certificate_key)
 * [lua_ssl_trusted_certificate](https://github.com/openresty/lua-nginx-module#lua_ssl_trusted_certificate)
 * [lua_ssl_verify_depth](https://github.com/openresty/lua-nginx-module#lua_ssl_verify_depth)
+* [lua_ssl_key_log](https://github.com/openresty/lua-nginx-module#lua_ssl_key_log)
 * [lua_ssl_conf_command](https://github.com/openresty/lua-nginx-module#lua_ssl_conf_command)
 * [lua_check_client_abort](https://github.com/openresty/lua-nginx-module#lua_check_client_abort)
 * [lua_max_pending_timers](https://github.com/openresty/lua-nginx-module#lua_max_pending_timers)
diff --git a/src/ngx_stream_lua_common.h b/src/ngx_stream_lua_common.h
index 751a0f3b..beb6041f 100644
--- a/src/ngx_stream_lua_common.h
+++ b/src/ngx_stream_lua_common.h
@@ -256,6 +256,7 @@ struct ngx_stream_lua_srv_conf_s {
     ngx_uint_t              ssl_verify_depth;
     ngx_str_t               ssl_trusted_certificate;
     ngx_str_t               ssl_crl;
+    ngx_str_t               ssl_key_log;
 #if (nginx_version >= 1019004)
     ngx_array_t            *ssl_conf_commands;
 #endif
diff --git a/src/ngx_stream_lua_module.c b/src/ngx_stream_lua_module.c
index 2aa41ad5..d2cb619c 100644
--- a/src/ngx_stream_lua_module.c
+++ b/src/ngx_stream_lua_module.c
@@ -49,6 +49,11 @@ static char *ngx_stream_lua_lowat_check(ngx_conf_t *cf, void *post, void *data);
 #if (NGX_STREAM_SSL)
 static ngx_int_t ngx_stream_lua_set_ssl(ngx_conf_t *cf,
     ngx_stream_lua_loc_conf_t *llcf);
+static void key_log_callback(const ngx_ssl_conn_t *ssl_conn,
+    const char *line);
+static void ngx_stream_lua_ssl_cleanup_key_log(void *data);
+static ngx_int_t ngx_stream_lua_ssl_key_log(ngx_conf_t *cf, ngx_ssl_t *ssl,
+    ngx_str_t *file);
 #if (nginx_version >= 1019004)
 static char *ngx_stream_lua_ssl_conf_command_check(ngx_conf_t *cf, void *post,
     void *data);
@@ -453,6 +458,13 @@ static ngx_command_t ngx_stream_lua_cmds[] = {
       offsetof(ngx_stream_lua_srv_conf_t, ssl_crl),
       NULL },
 
+    { ngx_string("lua_ssl_key_log"),
+      NGX_STREAM_MAIN_CONF|NGX_STREAM_SRV_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_str_slot,
+      NGX_STREAM_SRV_CONF_OFFSET,
+      offsetof(ngx_stream_lua_srv_conf_t, ssl_key_log),
+      NULL },
+
 #if (nginx_version >= 1019004)
     { ngx_string("lua_ssl_conf_command"),
       NGX_STREAM_MAIN_CONF|NGX_STREAM_SRV_CONF|NGX_CONF_TAKE2,
@@ -975,6 +987,7 @@ ngx_stream_lua_merge_srv_conf(ngx_conf_t *cf, void *parent, void *child)
     ngx_conf_merge_str_value(conf->ssl_trusted_certificate,
                              prev->ssl_trusted_certificate, "");
     ngx_conf_merge_str_value(conf->ssl_crl, prev->ssl_crl, "");
+    ngx_conf_merge_str_value(conf->ssl_key_log, prev->ssl_key_log, "");
 #if (nginx_version >= 1019004)
     ngx_conf_merge_ptr_value(conf->ssl_conf_commands, prev->ssl_conf_commands,
                              NULL);
@@ -1105,6 +1118,12 @@ ngx_stream_lua_set_ssl(ngx_conf_t *cf, ngx_stream_lua_srv_conf_t *lscf)
         return NGX_ERROR;
     }
 
+    if (ngx_stream_lua_ssl_key_log(cf, lscf->ssl, &lscf->ssl_key_log)
+        != NGX_OK)
+    {
+        return NGX_ERROR;
+    }
+
 #if (nginx_version >= 1019004)
     if (ngx_ssl_conf_commands(cf, lscf->ssl, lscf->ssl_conf_commands)
         != NGX_OK)
@@ -1117,6 +1136,101 @@ ngx_stream_lua_set_ssl(ngx_conf_t *cf, ngx_stream_lua_srv_conf_t *lscf)
 }
 
 
+static void
+key_log_callback(const ngx_ssl_conn_t *ssl_conn, const char *line)
+{
+    ngx_stream_lua_ssl_key_log_t  *ssl_key_log;
+    ngx_connection_t              *c;
+
+    ssl_key_log = SSL_CTX_get_ex_data(SSL_get_SSL_CTX(ssl_conn),
+                                      ngx_stream_lua_ssl_key_log_index);
+    if (ssl_key_log == NULL) {
+        c = ngx_ssl_get_connection((ngx_ssl_conn_t *) ssl_conn);
+        ngx_ssl_error(NGX_LOG_DEBUG, c->log, 0, "get ssl key log failed");
+
+        return;
+    }
+
+    (void) ngx_write_fd(ssl_key_log->fd, (void *) line, ngx_strlen(line));
+    (void) ngx_write_fd(ssl_key_log->fd, (void *) "\n", 1);
+}
+
+
+static void
+ngx_stream_lua_ssl_cleanup_key_log(void *data)
+{
+    ngx_stream_lua_ssl_key_log_t  *ssl_key_log = data;
+
+    if (ngx_close_file(ssl_key_log->fd) == NGX_FILE_ERROR) {
+        ngx_ssl_error(NGX_LOG_ALERT, ssl_key_log->ssl->log, 0,
+                      ngx_close_file_n "(\"%V\") failed", ssl_key_log->name);
+    }
+}
+
+
+static ngx_int_t
+ngx_stream_lua_ssl_key_log(ngx_conf_t *cf, ngx_ssl_t *ssl, ngx_str_t *file)
+{
+    ngx_fd_t                       fd;
+    ngx_stream_lua_ssl_key_log_t  *ssl_key_log;
+    ngx_pool_cleanup_t            *cln;
+
+    if (!file->len) {
+        return NGX_OK;
+    }
+
+    if (ngx_conf_full_name(cf->cycle, file, 1) != NGX_OK) {
+        return NGX_ERROR;
+    }
+
+    if (ngx_stream_lua_ssl_init(cf->log) != NGX_OK) {
+        return NGX_ERROR;
+    }
+
+    /*
+     * append so that existing keylog file contents can be preserved
+     */
+    fd = ngx_open_file(file->data, NGX_FILE_APPEND, NGX_FILE_CREATE_OR_OPEN,
+                       NGX_FILE_DEFAULT_ACCESS);
+    if (fd == NGX_INVALID_FILE) {
+        ngx_ssl_error(NGX_LOG_EMERG, ssl->log, 0, ngx_open_file_n
+                      "(\"%V\") failed", file);
+        return NGX_ERROR;
+    }
+
+    ssl_key_log = ngx_palloc(cf->pool, sizeof(ngx_stream_lua_ssl_key_log_t));
+    if (ssl_key_log == NULL) {
+        ngx_ssl_error(NGX_LOG_EMERG, ssl->log, 0, "ngx_pcalloc() failed");
+        return NGX_ERROR;
+    }
+
+    ssl_key_log->ssl = ssl;
+    ssl_key_log->fd = fd;
+    ssl_key_log->name = *file;
+
+    if (SSL_CTX_set_ex_data(ssl->ctx, ngx_stream_lua_ssl_key_log_index,
+                            ssl_key_log) == 0)
+    {
+        ngx_ssl_error(NGX_LOG_EMERG, ssl->log, 0,
+                      "SSL_CTX_set_ex_data() failed");
+        return NGX_ERROR;
+    }
+
+    cln = ngx_pool_cleanup_add(cf->pool, 0);
+    if (cln == NULL) {
+        ngx_stream_lua_ssl_cleanup_key_log(ssl_key_log);
+        return NGX_ERROR;
+    }
+
+    cln->handler = ngx_stream_lua_ssl_cleanup_key_log;
+    cln->data = ssl_key_log;
+
+    SSL_CTX_set_keylog_callback(ssl->ctx, key_log_callback);
+
+    return NGX_OK;
+}
+
+
 #if (nginx_version >= 1019004)
 static char *
 ngx_stream_lua_ssl_conf_command_check(ngx_conf_t *cf, void *post, void *data)
diff --git a/src/ngx_stream_lua_ssl.c b/src/ngx_stream_lua_ssl.c
index 2a6a951d..dfb96c60 100644
--- a/src/ngx_stream_lua_ssl.c
+++ b/src/ngx_stream_lua_ssl.c
@@ -22,6 +22,7 @@
 
 
 int ngx_stream_lua_ssl_ctx_index = -1;
+int ngx_stream_lua_ssl_key_log_index = -1;
 
 
 ngx_int_t
@@ -40,6 +41,19 @@ ngx_stream_lua_ssl_init(ngx_log_t *log)
         }
     }
 
+    if (ngx_stream_lua_ssl_key_log_index == -1) {
+        ngx_stream_lua_ssl_key_log_index = SSL_get_ex_new_index(0, NULL,
+                                                                NULL,
+                                                                NULL,
+                                                                NULL);
+
+        if (ngx_stream_lua_ssl_key_log_index == -1) {
+            ngx_ssl_error(NGX_LOG_ALERT, log, 0,
+                          "lua: SSL_get_ex_new_index() for key log failed");
+            return NGX_ERROR;
+        }
+    }
+
     return NGX_OK;
 }
 
diff --git a/src/ngx_stream_lua_ssl.h b/src/ngx_stream_lua_ssl.h
index 352b709e..a7aa40b8 100644
--- a/src/ngx_stream_lua_ssl.h
+++ b/src/ngx_stream_lua_ssl.h
@@ -49,10 +49,18 @@ typedef struct {
 } ngx_stream_lua_ssl_ctx_t;
 
 
+typedef struct {
+    ngx_ssl_t     *ssl;
+    ngx_fd_t       fd;
+    ngx_str_t      name;
+} ngx_stream_lua_ssl_key_log_t;
+
+
 ngx_int_t ngx_stream_lua_ssl_init(ngx_log_t *log);
 
 
 extern int ngx_stream_lua_ssl_ctx_index;
+extern int ngx_stream_lua_ssl_key_log_index;
 
 
 #endif
diff --git a/t/129-ssl-socket.t b/t/129-ssl-socket.t
index 79611cba..13fc9e84 100644
--- a/t/129-ssl-socket.t
+++ b/t/129-ssl-socket.t
@@ -3012,3 +3012,108 @@ handshake rejected while SSL handshaking
 [crit]
 --- timeout: 5
 --- skip_nginx: 7: < 1.25.4
+
+
+
+=== TEST 37: lua_ssl_key_log directive
+--- skip_openssl: 8: < 1.1.1
+--- http_config
+    server {
+        listen              unix:$TEST_NGINX_HTML_DIR/nginx.sock ssl;
+        server_name         test.com;
+        ssl_certificate     $TEST_NGINX_CERT_DIR/cert/test.crt;
+        ssl_certificate_key $TEST_NGINX_CERT_DIR/cert/test.key;
+        ssl_protocols       TLSv1.3;
+
+        location / {
+            content_by_lua_block {
+                ngx.exit(200)
+            }
+        }
+    }
+--- stream_server_config
+    lua_ssl_protocols TLSv1.3;
+    lua_ssl_key_log sslkey.log;
+
+    content_by_lua_block {
+        local sock = ngx.socket.tcp()
+        sock:settimeout(2000)
+
+        do
+            local ok, err = sock:connect("unix:$TEST_NGINX_HTML_DIR/nginx.sock")
+            if not ok then
+                ngx.say("failed to connect: ", err)
+                return
+            end
+
+            ngx.say("connected: ", ok)
+
+            local session, err = sock:sslhandshake(nil, "test.com")
+            if not session then
+                ngx.say("failed to do SSL handshake: ", err)
+                return
+            end
+
+            ngx.say("ssl handshake: ", type(session))
+
+            local req = "GET / HTTP/1.1\r\nHost: test.com\r\nConnection: close\r\n\r\n"
+            local bytes, err = sock:send(req)
+            if not bytes then
+                ngx.say("failed to send stream request: ", err)
+                return
+            end
+
+            ngx.say("sent stream request: ", bytes, " bytes.")
+
+            local line, err = sock:receive()
+            if not line then
+                ngx.say("failed to recieve response status line: ", err)
+                return
+            end
+
+            ngx.say("received: ", line)
+
+            local ok, err = sock:close()
+            ngx.say("close: ", ok, " ", err)
+
+            local f, err = io.open("$TEST_NGINX_SERVER_ROOT/conf/sslkey.log", "r")
+            if not f then
+                ngx.log(ngx.ERR, "failed to open sslkey.log: ", err)
+                return
+            end
+
+            local key_log = f:read("*a")
+            ngx.say(key_log)
+            f:close()
+        end  -- do
+        collectgarbage()
+    }
+
+--- stream_response_like
+connected: 1
+ssl handshake: userdata
+sent stream request: 53 bytes.
+received: HTTP/1.1 200 OK
+close: 1 nil
+SERVER_HANDSHAKE_TRAFFIC_SECRET [0-9a-z\s]+
+EXPORTER_SECRET [0-9a-z\s]+
+SERVER_TRAFFIC_SECRET_0 [0-9a-z\s]+
+CLIENT_HANDSHAKE_TRAFFIC_SECRET [0-9a-z\s]+
+CLIENT_TRAFFIC_SECRET_0 [0-9a-z\s]+
+
+--- log_level: debug
+--- grep_error_log eval: qr/lua ssl (?:set|save|free) session: [0-9A-F]+/
+--- grep_error_log_out eval
+qr/^lua ssl save session: ([0-9A-F]+)
+lua ssl free session: ([0-9A-F]+)
+$/
+--- error_log eval
+[
+'lua ssl server name: "test.com"',
+qr/SSL: TLSv1.3, cipher: "(TLS_AES_256_GCM_SHA384 TLSv1.3|TLS_AES_128_GCM_SHA256 Kx=GENERIC Au=GENERIC Enc=AESGCM\(128\) Mac=AEAD)/,
+]
+--- no_error_log
+SSL reused session
+[error]
+[alert]
+--- timeout: 10