Earth 616: It is unknown, for the Hulk's strength increases to potentially unlimited levels, whereas Thor possesses overall an incalculable level of superhuman strength in his arsenal. Both have stalemated characters wielding unlimited strength such as Hercules. It can be said that the Hulk, at his angriest state, could be stronger than Thor, however, Thor has claimed to withhold his power and strength while fighting on Earth. Also, Thor has feats that could overall keep his strength level nearly on par, if not on par with the strongest incarnations of the Hulk/
Ultimate: Hulk's peak strength is greater than Thor's, meaning he's physically stronger
Movie verse : Hulk is physically stronger, but Thor with Mjolnir matches Hulk's force output.