But would you invite your MIL on your hen do?

[Rosienose]

Just that really I didn’t realise it was a thing.

you are being unreasonable - Yes you should

you are NOT being unreasonable - Perfectlg acceptable not to invite them

I went on my DIL hen night 20 years ago , saying that I was only 50 which is the age of a lot of brides these days 😀

I had two… a night out with all my friends in a neighbouring city, and a house hen organised by my sister that my future MIL, SIL, cousins and aunties attended. It was lovely, and a great opportunity for both sides of the family to meet in advance of the wedding

No absolutely not because she was miserable and ruined everything else she was invited too. However had we got along even on a basic level yes I would invite and caveat love you to be there

And of course you do NOT have to invite your MIL if you invite your mum. She's not your mum. Not that you gave any indication of you inviting your mum, which is also not generally a thing.

There's no "depends" on anything it is entirely and only your choice.

But it would be very weird indeed if your MIL expected an invitation, and it's a good red flag to take notice of if this is what is happening.

I think there are multiple factors involved to say a definite yes or no. What the relationship between the two of you is like, what the activity is that is taking place, and whether MIL would want to take part or not, the number of people going and how many of them are also family/people MIL would know, or are they all friends/work friends etc. I invited my MIL to my Hen night. However, we went out for a meal. I also invited my Mum, my Aunt, my SIL, my flower girl (who was about 10), my matron of honour and her mum. if it had been a night out at a bar or club, then no i wouldn't have invited her, but probably would have had a second one to include her, my mum etc. I am fortunate to get on well with my MIL and speak to her as often as I speak to my mum.