diff --git a/docs/topics/spider-middleware.rst b/docs/topics/spider-middleware.rst
index a38c1ab65..604f1864f 100644
--- a/docs/topics/spider-middleware.rst
+++ b/docs/topics/spider-middleware.rst
@@ -28,7 +28,12 @@ The :setting:`SPIDER_MIDDLEWARES` setting is merged with the
 :setting:`SPIDER_MIDDLEWARES_BASE` setting defined in Scrapy (and not meant to
 be overridden) and then sorted by order to get the final sorted list of enabled
 middlewares: the first middleware is the one closer to the engine and the last
-is the one closer to the spider.
+is the one closer to the spider. In other words,
+the :meth:`~scrapy.spidermiddlewares.SpiderMiddleware.process_spider_input`
+method of each middleware will be invoked in increasing
+middleware order (100, 200, 300, ...), and the
+:meth:`~scrapy.spidermiddlewares.SpiderMiddleware.process_spider_output` method
+of each middleware will be invoked in decreasing order.
 
 To decide which order to assign to your middleware see the
 :setting:`SPIDER_MIDDLEWARES_BASE` setting and pick a value according to where