In Torchlight there are wearable rings that boost experience gain by a percentage. If I equip my pet with one of these rings, will this increase the experience gain of my player?
It is unlikely that your pet’s +%xp affects your own.
Looking at the similar stat of +% magic find, I know that if you give your pet +Magic Find items, they will benefit from the magic find only when they kill things (as opposed to you killing them. Your pet has magic find = to your magic find + any magic find items worn by the pet.
But the way this concept would work for XP is, if you have a +3% xp ring, and your pet has a +2% xp ring, you would get 103% XP, and your pet would get 105% (all of your xp%, + it’s own). However, since pets don’t accrue experience, this is irrelevant.