Fact: Freemasonry is not a Religion

This explanation from askafreemason.org sums it up best:

Masonry is not a religion. But it is one of the few platforms where men of all faiths - Christians, including Catholics, Jews, Muslims, and men of every other faith - can come together because it is open to all men who believe in a Supreme Being; but religion is not discussed at Masonic meetings. Although Lodges open and close with a prayer and Masonry teaches morality, it is not a church or a religion. Masonry does not have a theology or dogma, it does not offer sacraments, and it does not offer the promise of salvation.

Another occasional point of confusion is that the buildings where Masons meet are sometimes called "Masonic Temples" - this is simply an allusion to King Solomon's Temple, a structure that figures prominently in the three degrees of Freemasonry.