diff --git a/scrapy/core/downloader/webclient.py b/scrapy/core/downloader/webclient.py
index 915cb5fe3..06cb96489 100644
--- a/scrapy/core/downloader/webclient.py
+++ b/scrapy/core/downloader/webclient.py
@@ -3,7 +3,7 @@ from time import time
 from urllib.parse import urlparse, urlunparse, urldefrag
 
 from twisted.web.http import HTTPClient
-from twisted.internet import defer, reactor
+from twisted.internet import defer
 from twisted.internet.protocol import ClientFactory
 
 from scrapy.http import Headers
@@ -170,6 +170,7 @@ class ScrapyHTTPClientFactory(ClientFactory):
         p.followRedirect = self.followRedirect
         p.afterFoundGet = self.afterFoundGet
         if self.timeout:
+            from twisted.internet import reactor
             timeoutCall = reactor.callLater(self.timeout, p.timeout)
             self.deferred.addBoth(self._cancelTimeout, timeoutCall)
         return p