Should I get my coworker a gift?

I'd probably just write him a nice card, and if you're more friends-who-work-together than friendly-faces-at-work, maybe include a gift card too.

I think a card with either a gift card or a smallish item off the registry is a nice gesture. I have done it in the past for co-workers and it didn't make things weird.

I would give a gift if it was me, it's a nice gesture. most understand how challenging a wedding guest list can be, so I wouldn't worry about it too much.

I wouldn't give him a gift. Maybe a nice card and a small gift card or something. I have a lot of coworkers that I work with on a daily basis but am not inviting them because we aren't close. I wouldn't expect them to get me something either. I would feel very awkward if they did end up getting me something, but I would think a sweet card would be nice and appreciated. With or without a gift card.

A card, and maybe a small gift or gift card I think would be fine. I don't think it has to be off his registry necessarily, just some small token gift would be a sweet gesture.

Maybe a picture frame so he can have a wedding pic on his desk?

I WOULD get him something...I would just look up their wedding registry and get something off of it, $50 gift or so

I would, but maybe give it to him after his wedding, that way he doesn't feel bad about not inviting you to his. Maybe have it when he goes back to work