diff --git a/lib/adapters/http.js b/lib/adapters/http.js
index f32241f77e..095cde04a0 100755
--- a/lib/adapters/http.js
+++ b/lib/adapters/http.js
@@ -54,9 +54,18 @@ module.exports = function httpAdapter(config) {
     var headers = config.headers;
 
     // Set User-Agent (required by some servers)
-    // Only set header if it hasn't been set in config
     // See https://github.com/axios/axios/issues/69
-    if (!headers['User-Agent'] && !headers['user-agent']) {
+    if ('User-Agent' in headers || 'user-agent' in headers) {
+      // User-Agent is specified; handle case where no UA header is desired
+      let useragent = headers['User-Agent'] || headers['user-agent'];
+      if (!useragent) {
+        delete headers['User-Agent'];
+        delete headers['user-agent'];
+      }
+      // Otherwise, use specified value
+    }
+    else {
+      // Only set header if it hasn't been set in config
       headers['User-Agent'] = 'axios/' + pkg.version;
     }