diff --git a/include/sentry.h b/include/sentry.h
index 43203151a..03f1bb641 100644
--- a/include/sentry.h
+++ b/include/sentry.h
@@ -1253,6 +1253,12 @@ SENTRY_API uint64_t sentry_options_get_shutdown_timeout(sentry_options_t *opts);
 SENTRY_API void sentry_options_set_backend(
     sentry_options_t *opts, sentry_backend_t *backend);
 
+/**
+ * Sets a user-defined user-agent.
+ */
+SENTRY_API void sentry_options_set_app_user_agent(
+    sentry_options_t *opts, const char *app_user_agent);
+
 /* -- Global APIs -- */
 
 /**
diff --git a/src/sentry_options.c b/src/sentry_options.c
index 014ec491f..eee135b0a 100644
--- a/src/sentry_options.c
+++ b/src/sentry_options.c
@@ -87,6 +87,7 @@ sentry_options_free(sentry_options_t *opts)
     sentry_free(opts->release);
     sentry_free(opts->sdk_name);
     sentry_free(opts->user_agent);
+    sentry_free(opts->app_user_agent);
     sentry_free(opts->environment);
     sentry_free(opts->dist);
     sentry_free(opts->http_proxy);
@@ -594,3 +595,11 @@ sentry_options_set_backend(sentry_options_t *opts, sentry_backend_t *backend)
     sentry__backend_free(opts->backend);
     opts->backend = backend;
 }
+
+void
+sentry_options_set_app_user_agent(
+    sentry_options_t *opts, const char *app_user_agent)
+{
+    sentry_free(opts->app_user_agent);
+    opts->app_user_agent = sentry__string_clone(app_user_agent);
+}
diff --git a/src/sentry_options.h b/src/sentry_options.h
index 060b17f70..0d80e916f 100644
--- a/src/sentry_options.h
+++ b/src/sentry_options.h
@@ -40,6 +40,7 @@ typedef struct sentry_options_s {
     char *transport_thread_name;
     char *sdk_name;
     char *user_agent;
+    char *app_user_agent;
     sentry_path_t *database_path;
     sentry_path_t *handler_path;
     sentry_logger_t logger;
diff --git a/src/transports/sentry_transport_curl.c b/src/transports/sentry_transport_curl.c
index 11f87e5d2..bbb2d4e0d 100644
--- a/src/transports/sentry_transport_curl.c
+++ b/src/transports/sentry_transport_curl.c
@@ -203,6 +203,7 @@ sentry__curl_send_task(void *_envelope, void *_state)
     curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);
     curl_easy_setopt(curl, CURLOPT_POSTFIELDS, req->body);
     curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, (long)req->body_len);
+    // TODO: curl 支持 app_user_agent
     curl_easy_setopt(curl, CURLOPT_USERAGENT, SENTRY_SDK_USER_AGENT);
 
     char error_buf[CURL_ERROR_SIZE];
diff --git a/src/transports/sentry_transport_winhttp.c b/src/transports/sentry_transport_winhttp.c
index ffb114eb9..40d5c8f04 100644
--- a/src/transports/sentry_transport_winhttp.c
+++ b/src/transports/sentry_transport_winhttp.c
@@ -64,6 +64,15 @@ sentry__winhttp_transport_start(
 
     state->dsn = sentry__dsn_incref(opts->dsn);
     state->user_agent = sentry__string_to_wstr(opts->user_agent);
+    wchar_t *full_user_agent = state->user_agent;
+    bool user_agent_owned = false;
+    if (opts->app_user_agent) {
+        char user_agent[255];
+        snprintf(user_agent, sizeof(user_agent), "%s %s", opts->app_user_agent,
+            opts->user_agent);
+        full_user_agent = sentry__string_to_wstr(user_agent);
+        user_agent_owned = true;
+    }
     state->debug = opts->debug;
 
     sentry__bgworker_setname(bgworker, opts->transport_thread_name);
@@ -84,22 +93,25 @@ sentry__winhttp_transport_start(
 
     if (state->proxy) {
         state->session
-            = WinHttpOpen(state->user_agent, WINHTTP_ACCESS_TYPE_NAMED_PROXY,
+            = WinHttpOpen(full_user_agent, WINHTTP_ACCESS_TYPE_NAMED_PROXY,
                 state->proxy, WINHTTP_NO_PROXY_BYPASS, 0);
     } else {
 #if _WIN32_WINNT >= 0x0603
-        state->session = WinHttpOpen(state->user_agent,
+        state->session = WinHttpOpen(full_user_agent,
             WINHTTP_ACCESS_TYPE_AUTOMATIC_PROXY, WINHTTP_NO_PROXY_NAME,
             WINHTTP_NO_PROXY_BYPASS, 0);
 #endif
         // On windows 8.0 or lower, WINHTTP_ACCESS_TYPE_AUTOMATIC_PROXY does
         // not work on error we fallback to WINHTTP_ACCESS_TYPE_DEFAULT_PROXY
         if (!state->session) {
-            state->session = WinHttpOpen(state->user_agent,
+            state->session = WinHttpOpen(full_user_agent,
                 WINHTTP_ACCESS_TYPE_DEFAULT_PROXY, WINHTTP_NO_PROXY_NAME,
                 WINHTTP_NO_PROXY_BYPASS, 0);
         }
     }
+    if (user_agent_owned) {
+        sentry_free(full_user_agent);
+    }
     if (!state->session) {
         SENTRY_WARN("`WinHttpOpen` failed");
         return 1;