diff --git a/src/MQTTAsync.h b/src/MQTTAsync.h
index 3d597ce0..3c8daa88 100644
--- a/src/MQTTAsync.h
+++ b/src/MQTTAsync.h
@@ -78,6 +78,7 @@
  * <li>@ref tracing</li>
  * <li>@ref auto_reconnect</li>
  * <li>@ref offline_publish</li>
+ * <li>@ref HTTP_proxies</li>
  * </ul>
  * @endcond
  */
@@ -1374,11 +1375,13 @@ typedef struct
 	 */
 	const MQTTAsync_nameValue* httpHeaders;
 	/**
-	 * HTTP proxy
-	 */
+	* The string value of the HTTP proxy. Examples:
+    *  - http://your.proxy.server:8080/
+    *  - http://user:pass@my.proxy.server:8080/
+	*/
 	const char* httpProxy;
 	/**
-	 * HTTPS proxy
+	 * HTTPS proxy setting. See ::MQTTAsync_connectOptions.httpProxy and the section @ref HTTP_proxies.
 	 */
 	const char* httpsProxy;
 } MQTTAsync_connectOptions;
@@ -2377,6 +2380,17 @@ exit:
     20130528 163909.209 Heap scan end
   * @endcode
   * @endcond
+  *
+√* @page HTTP_proxies HTTP Proxies
+  * The use of HTTP proxies can be controlled by environment variables or API calls.
+  *
+  * The ::MQTTAsync_connectOptions.httpProxy and ::MQTTAsync_connectOptions.httpsProxy fields
+  * of the ::MQTTAsync_connectOptions structure override any settings in the environment.
+  *
+  * If the environment variable PAHO_C_CLIENT_USE_HTTP_PROXY is set to TRUE, then the
+  * http_proxy or https_proxy environment variables are used, for plain TCP and TLS-secured
+  * connections respectively.
+  *
   */
 
 #if defined(__cplusplus)
diff --git a/src/MQTTClient.h b/src/MQTTClient.h
index 38aa1836..779fd9a2 100644
--- a/src/MQTTClient.h
+++ b/src/MQTTClient.h
@@ -97,6 +97,7 @@
  * <li>@ref wildcard</li>
  * <li>@ref qos</li>
  * <li>@ref tracing</li>
+ * <li>@ref HTTP_proxies</li>
  * </ul>
  * @endcond
  */
@@ -971,12 +972,14 @@ typedef struct
 	 */
 	const MQTTClient_nameValue* httpHeaders;
 	/**
-	 * HTTP proxy
-	 */
+	* The string value of the HTTP proxy. Examples:
+	*  - http://your.proxy.server:8080/
+	*  - http://user:pass@my.proxy.server:8080/
+	*/
 	const char* httpProxy;
 	/**
-	 * HTTPS proxy
-	 */
+	* HTTPS proxy setting. See ::MQTTClient_connectOptions.httpProxy and the section @ref HTTP_proxies.
+	*/
 	const char* httpsProxy;
 } MQTTClient_connectOptions;
 
@@ -1979,4 +1982,15 @@ exit:
     20130528 163909.209 Heap scan end
   * @endcode
   * @endcond
+  *
+* √* @page HTTP_proxies HTTP Proxies
+  * The use of HTTP proxies can be controlled by environment variables or API calls.
+  *
+  * The ::MQTTClient_connectOptions.httpProxy and ::MQTTClient_connectOptions.httpsProxy fields
+  * of the ::MQTTClient_connectOptions structure override any settings in the environment.
+  *
+  * If the environment variable PAHO_C_CLIENT_USE_HTTP_PROXY is set to TRUE, then the
+  * http_proxy or https_proxy environment variables are used, for plain TCP and TLS-secured
+  * connections respectively.
+  *
   */
diff --git a/src/MQTTProtocolOut.c b/src/MQTTProtocolOut.c
index a7ad694f..1028737f 100644
--- a/src/MQTTProtocolOut.c
+++ b/src/MQTTProtocolOut.c
@@ -222,7 +222,7 @@ int MQTTProtocol_connect(const char* ip_address, Clients* aClient, int websocket
 	int rc = 0,
 		port;
 	size_t addr_len;
-	char* p0;
+	char* p0 = NULL;
 
 	FUNC_ENTRY;
 	aClient->good = 1;
@@ -230,7 +230,15 @@ int MQTTProtocol_connect(const char* ip_address, Clients* aClient, int websocket
 	if (aClient->httpProxy)
 		p0 = aClient->httpProxy;
 	else
-		p0 = getenv("http_proxy");
+	{
+		/* Don't use the environment HTTP proxy settings by default - for backwards compatibility */
+		char* use_proxy = getenv("PAHO_C_CLIENT_USE_HTTP_PROXY");
+		if (use_proxy)
+		{
+			if (strncmp(use_proxy, "TRUE", strlen("TRUE")) == 0)
+				p0 = getenv("http_proxy");
+		}
+	}
 
 	if (p0)
 	{