diff --git a/curl-sys/lib.rs b/curl-sys/lib.rs
index 5e5b10c28..555c86034 100644
--- a/curl-sys/lib.rs
+++ b/curl-sys/lib.rs
@@ -303,6 +303,9 @@ pub const CURLPROXY_SOCKS5: curl_proxytype = 5;
 pub const CURLPROXY_SOCKS4A: curl_proxytype = 6;
 pub const CURLPROXY_SOCKS5_HOSTNAME: curl_proxytype = 7;
 
+pub const CURLHEADER_UNIFIED: c_long = 0;
+pub const CURLHEADER_SEPARATE: c_long = 1 << 0;
+
 pub const CURLAUTH_NONE: c_ulong = 0;
 pub const CURLAUTH_BASIC: c_ulong = 1 << 0;
 pub const CURLAUTH_DIGEST: c_ulong = 1 << 1;
@@ -595,6 +598,7 @@ pub const CURLOPT_SSL_OPTIONS: CURLoption = CURLOPTTYPE_LONG + 216;
 // pub const CURLOPT_LOGIN_OPTIONS: CURLoption = CURLOPTTYPE_OBJECTPOINT + 224;
 pub const CURLOPT_EXPECT_100_TIMEOUT_MS: CURLoption = CURLOPTTYPE_LONG + 227;
 pub const CURLOPT_PROXYHEADER: CURLoption = CURLOPTTYPE_OBJECTPOINT + 228;
+pub const CURLOPT_HEADEROPT: CURLoption = CURLOPTTYPE_LONG + 229;
 pub const CURLOPT_PINNEDPUBLICKEY: CURLoption = CURLOPTTYPE_OBJECTPOINT + 230;
 pub const CURLOPT_UNIX_SOCKET_PATH: CURLoption = CURLOPTTYPE_OBJECTPOINT + 231;
 pub const CURLOPT_PATH_AS_IS: CURLoption = CURLOPTTYPE_LONG + 234;
diff --git a/src/easy/handle.rs b/src/easy/handle.rs
index 10bcce350..2a12a9566 100644
--- a/src/easy/handle.rs
+++ b/src/easy/handle.rs
@@ -851,6 +851,11 @@ impl Easy {
         self.inner.proxy_headers(list)
     }
 
+    /// Same as [`Easy2::proxy_headers_separate`](struct.Easy2.html#method.proxy_headers_separate)
+    pub fn proxy_headers_separate(&mut self, separate: bool) -> Result<(), Error> {
+        self.inner.proxy_headers_separate(separate)
+    }
+
     /// Same as [`Easy2::cookie`](struct.Easy2.html#method.cookie)
     pub fn cookie(&mut self, cookie: &str) -> Result<(), Error> {
         self.inner.cookie(cookie)
diff --git a/src/easy/handler.rs b/src/easy/handler.rs
index d9aa7b6ff..900a90b0c 100644
--- a/src/easy/handler.rs
+++ b/src/easy/handler.rs
@@ -1598,7 +1598,9 @@ impl<H> Easy2<H> {
 
     /// Add some headers to send to the HTTP proxy.
     ///
-    /// This function is essentially the same as `http_headers`.
+    /// This function is essentially the same as `http_headers`, but libcurl
+    /// only uses the list once [`proxy_headers_separate`](Easy2::proxy_headers_separate)
+    /// is on.
     ///
     /// By default this option is not set and corresponds to
     /// `CURLOPT_PROXYHEADER`
@@ -1608,6 +1610,26 @@ impl<H> Easy2<H> {
         self.setopt_ptr(curl_sys::CURLOPT_PROXYHEADER, ptr as *const _)
     }
 
+    /// Keep the headers for the proxy apart from the headers for the server.
+    ///
+    /// Off, libcurl's default, the `http_headers` list is also sent to the
+    /// proxy in a `CONNECT` request, which hands an `Authorization` or
+    /// `Cookie` header meant for the server to the proxy, and the
+    /// `proxy_headers` list is ignored. On, `http_headers` go only to the
+    /// server and `proxy_headers` only to the proxy; a request that is not
+    /// a `CONNECT` (plain `http://` through a proxy) gets both lists.
+    ///
+    /// By default this option is `false` and corresponds to
+    /// `CURLOPT_HEADEROPT` with `CURLHEADER_SEPARATE`.
+    pub fn proxy_headers_separate(&mut self, separate: bool) -> Result<(), Error> {
+        let mode = if separate {
+            curl_sys::CURLHEADER_SEPARATE
+        } else {
+            curl_sys::CURLHEADER_UNIFIED
+        };
+        self.setopt_long(curl_sys::CURLOPT_HEADEROPT, mode)
+    }
+
     /// Set the contents of the HTTP Cookie header.
     ///
     /// Pass a string of the form `name=contents` for one cookie value or
diff --git a/tests/easy.rs b/tests/easy.rs
index b3fde1828..a36105870 100644
--- a/tests/easy.rs
+++ b/tests/easy.rs
@@ -1035,3 +1035,37 @@ fn test_timeout() {
             .unwrap()
     );
 }
+
+#[test]
+fn proxy_headers_need_separate_mode() {
+    // the server plays a plain-http proxy, which gets both lists once the
+    // headers are kept separate and only the server list before
+    for (separate, expect_proxy_header) in [(false, false), (true, true)] {
+        let s = Server::new();
+        let mut expected = String::from(
+            "\
+             GET http://origin.invalid/ HTTP/1.1\r\n\
+             Host: origin.invalid\r\n\
+             Accept: */*\r\n\
+             X-Server: 1\r\n",
+        );
+        if expect_proxy_header {
+            expected.push_str("X-Proxy: 1\r\n");
+        }
+        expected.push_str("\r\n");
+        s.receive(&expected);
+        s.send("HTTP/1.1 200 OK\r\n\r\n");
+
+        let mut handle = handle();
+        t!(handle.url("http://origin.invalid/"));
+        t!(handle.proxy(&s.url("")));
+        let mut server_headers = List::new();
+        t!(server_headers.append("X-Server: 1"));
+        t!(handle.http_headers(server_headers));
+        let mut proxy_headers = List::new();
+        t!(proxy_headers.append("X-Proxy: 1"));
+        t!(handle.proxy_headers(proxy_headers));
+        t!(handle.proxy_headers_separate(separate));
+        t!(handle.perform());
+    }
+}