This article is from the Toyota RAV4 FAQ, by Ralph Becker with numerous contributions by others.
According to the Crutchfield <http://www.crutchfield.com/>
Rear speakers: 6.25"
Door speakers: 6.25" (limited clearance (0.6") between speaker & door panel)
Note: '96 models and some early '97 2-door models may accept only
5.5" speakers in the front doors. Also received a report that
the rear speaker location will only accepts a 5.5" in some models.