Is it OK to invite people to your hen/stag do even if they aren’t invited to the wedding?

Great question! Of course it is, but be prepared to explain just in case you are asked why they weren’t invited in the first place.

If you have a legitimate reason for not inviting someone to the actual wedding, but would very much like them to attend your hen’s/stag’s night (ie. you are having an intimate family-only ceremony etc) tell them that.

Explain your reasons and they may very well understand, which is the best possible solution because nobody gets hurt; You have your friend in attendance on one of your truly special days and they don’t feel like they’ve been snubbed.

Related link: How do I tell someone they’re not invited to my wedding?