diff --git a/httplib.h b/httplib.h
index 65de818..4607342 100644
--- a/httplib.h
+++ b/httplib.h
@@ -52,6 +52,7 @@ typedef int socket_t;
 #include <functional>
 #include <map>
 #include <memory>
+#include <mutex>
 #include <regex>
 #include <string>
 #include <thread>
@@ -204,6 +205,8 @@ public:
     bool is_running() const;
     void stop();
 
+    bool is_handling_requests() const;
+
 protected:
     bool process_request(Stream& strm, bool last_connection);
 
@@ -231,6 +234,10 @@ private:
     Handlers    post_handlers_;
     Handler     error_handler_;
     Logger      logger_;
+
+    // TODO: Use thread pool...
+    std::mutex  running_threads_mutex_;
+    int         running_threads_;
 };
 
 class Client {
@@ -1407,6 +1414,7 @@ inline std::string SocketStream::get_remote_addr() {
 inline Server::Server(HttpVersion http_version)
     : http_version_(http_version)
     , svr_sock_(-1)
+    , running_threads_(0)
 {
 #ifndef _WIN32
     signal(SIGPIPE, SIG_IGN);
@@ -1476,6 +1484,11 @@ inline void Server::stop()
     svr_sock_ = -1;
 }
 
+inline bool Server::is_handling_requests() const
+{
+    return running_threads_ > 0;
+}
+
 inline bool Server::parse_request_line(const char* s, Request& req)
 {
     static std::regex re("(GET|HEAD|POST) ([^?]+)(?:\\?(.+?))? (HTTP/1\\.[01])\r\n");
@@ -1632,10 +1645,29 @@ inline bool Server::listen_internal()
 
         // TODO: Use thread pool...
         std::thread([=]() {
+            {
+                std::lock_guard<std::mutex> guard(running_threads_mutex_);
+                running_threads_++;
+            }
+
             read_and_close_socket(sock);
+
+            {
+                std::lock_guard<std::mutex> guard(running_threads_mutex_);
+                running_threads_--;
+            }
         }).detach();
     }
 
+    // TODO: Use thread pool...
+    for (;;) {
+        std::this_thread::sleep_for(std::chrono::milliseconds(10));
+        std::lock_guard<std::mutex> guard(running_threads_mutex_);
+        if (!running_threads_) {
+            break;
+        }
+    }
+
     return ret;
 }
 
diff --git a/test/test.cc b/test/test.cc
index de2ebf2..2e91ad7 100644
--- a/test/test.cc
+++ b/test/test.cc
@@ -262,6 +262,10 @@ protected:
         svr_.get("/hi", [&](const Request& /*req*/, Response& res) {
                 res.set_content("Hello World!", "text/plain");
             })
+            .get("/slow", [&](const Request& /*req*/, Response& res) {
+                msleep(3000);
+                res.set_content("slow", "text/plain");
+            })
             .get("/remote_addr", [&](const Request& req, Response& res) {
                 auto remote_addr = req.headers.find("REMOTE_ADDR")->second;
                 res.set_content(remote_addr.c_str(), "text/plain");
@@ -358,6 +362,7 @@ protected:
     virtual void TearDown() {
         svr_.stop();
         t_.join();
+        EXPECT_EQ(false, svr_.is_handling_requests());
     }
 
     map<string, string> persons_;
@@ -664,6 +669,14 @@ TEST_F(ServerTest, GetMethodRemoteAddr)
     EXPECT_TRUE(res->body == "::1" || res->body == "127.0.0.1");
 }
 
+TEST_F(ServerTest, SlowRequest)
+{
+    std::thread([=]() { auto res = cli_.get("/slow"); }).detach();
+    std::thread([=]() { auto res = cli_.get("/slow"); }).detach();
+    std::thread([=]() { auto res = cli_.get("/slow"); }).detach();
+    msleep(1000);
+}
+
 #ifdef CPPHTTPLIB_ZLIB_SUPPORT
 TEST_F(ServerTest, Gzip)
 {