Tumblr is a website where anyone can write or collect multimedia posts on a personal blog.

The users who have created a total of 340 million Tumblr blogs tend, though not unanimously, to be part of the fandom community, sharing photos and exclamations about the things they really like. Fortunately, and not surprisingly, for many of them the thing they like is Sherlock Holmes, particularly as he's portrayed on screen by Benedict Cumberbatch, Robert Downey Jr., or both.

This list of Tumblrs is curated for relevance to Holmes, but not for quality, sound judgment, or suitability for family audiences. A number of them depend to some degree on sexually explicit fan fiction and fan art, though it may be difficult to tell based on name alone.