According to the editors of Yale Alumni Magazine — which has devoted three separate articles to the topic, in an attempt to court fictional alumnus ducats — Bruce Wayne received a law degree from Yale.
Comic historian Chip Kidd lays out the single panel of evidence...
It is a detail of the last panel of a 14-page comic book story called "Night of the Stalker," originally appearing in 1974 in Detective Comics #439. First of all, this is a great story, with writing by Steve Englehart and art by Sal Amendola and Dick Giordano [...] In the background of this last panel, on the wall, is a framed document, a diploma. Using an extremely strong magnifying glass you can just barely make out that it's from . . . the Yale Law School. I bow to the eagle-eyed sleuth who discovered it. I have re-read the story countless times over the years and never before noticed this tiny detail.
Incidentally, I seem to remember an issue of The Champions in which Ghost Rider owns up to being a Vassar man.* Moving on, Yale law librarian Fred R. Shapiro discusses how Batman actually attended a Yale satellite campus...
Its wording and format are highly unusual. And its geographic references are mysterious: the diploma is from YALE UNIVERSITY AT GOTHAM, with NEW HAVEN appearing below GOTHAM. We can only speculate that, in the Bat-universe, Yale Law School has a branch campus in Gotham City.
And panel artist Sal Amendola explains why he gave Bruce Wayne a law degree...
I always thought of him as a dual personality. As Bruce Wayne he is a bleeding-heart liberal do-gooder, and as Batman he is a vigilante conservative.
And finally Kidd notes that Bruce Wayne's great-grandfather founded Skull and Bones on the Batman TV show — was Bruce a legacy candidate? Folks may argue that the TV show is out of continuity, but Batman writer Grant Morrison's been A.) folding all sorts of 1960s craziness into Bat mythology as of late; and B.) been big on the Wayne family's participation in sinister secret societies. Let's call it a gray area.
*Making this up.