WARNING: SOAPBOXY, OKAY TO SKIP
Short version: no.
Long version: noooooooooo.
Long version with elaboration:
The Oxford Dictionaries definition of religion is “the belief in and worship of a superhuman controlling power, especially a personal God or gods”.
Given that atheism is the explicit rejection of that exact hypothesis…I probably don’t need to elaborate on that.
But even without a dictionary, atheism is not a religion unless your definition of “religion” is too broad to be of any use whatsoever.
Atheism is, by and large, devoid of the ritual that characterises faith. Atheists might attend speeches, but most of us don’t attend weekly sermons. There are no atheist hymns, although John Lennon’s Imagine and the Galaxy Song from Monty Python come close. Atheism doesn’t do feast days or prayers. Confession is between you and the cops. And so on.
(Okay, if you define religion as “an opinion on the nature of the universe” atheism probably qualifies, but by that definition, physics, agnosticism, and I-don’t-care-and-will-you-all-shut-up-entology are also religions, hence my point about “too broad to be of any use”.)
– OSM out