AIBU - Mother in Law's dress at my wedding.

If she's generally a lovely person (which you have said she is) can you just tell her it's a lovely dress, but that she make look out of place as everyone else is wearing bright colours? Explain that she is one of the important guests and that she will be forever in the photos of the wedding party? Perhaps offer to go shopping with her? At the end of the day although it feels important now, it really isn't a biggie. The train is weird though..

What the fuck?!?!?!

can you get your DH to have a word?

Just seen your photo op, maybe is a bit much 🤣

Seriously? It didn't even occur to me to ask what colour my MIL was going to wear to our wedding (ours, not mine!!) She should be free to wear whatever suits her and she is comfortable in. It's one day

Love the dress, especially if she has the right figure, not for your wedding though.

a black outfit is absolutely fine for a wedding guest. It’s an unusual choice for a destination wedding but not inappropriate.

Black and a train? Maleficent? I’d explain what you want the vibe/photographs to be and offer a days shopping and lunch with her to get something appropriate.

My ‘dear’ mother wore black at my wedding, she’s quite obsessed with ‘the done thing’ and it was an entirely deliberate statement. Last I heard she makes everyone’s Christmas a misery by ranting about not knowing where I live and not having seen me for years.
I didn’t really notice at the time, just relieved she hadn’t done anything worse, I think. And yes, the guests thought she was a dick.

Assume it was a joke.

"For a moment I thought you were serious, and was just wondering how I could tell you how people would react to the mother of the bride looking like she'd turned up as a bride in black. Love to see your outfit when you've really chosen one. "

Crikey, you lot should have seen the grief my best friend got from her D-i-L-to-be, who vetoed several perfectly resaonable outfits (none of which was black or white,or even cream) and who turned out to be not only Bridezilla, but WifeZilla to boot.
Personally, I think everyone apart from the bridesmaids and groomsmen should just be able to choose their own clothes and not consult beforehand, although I can see that if both Mother and Mother-in-Law are going to be present, they might want to avoid anything too similar to each other.

It's almost as if she's saying she's in mourning for "the loss" of her son to his wife. I can't really visualise such a dress that doesn't seem bizarrely caricaturish. Will she look OK in it or ridiculous do you think? It sounds such a massive overstep .

Old women in black is very 'spanish'. I'd invite a few mature female locals and ask them to wear black with black lace mantillas.

These are beautiful 😍 ❤️

I don’t think you can tell her not to wear black, or that she must fit in with your ‘colour palette’. Nor would I assume she’s lost the plot or anything, it may just be a cultural thing i.e. all the American weddings I’ve attended have been black tie or black tie optional and the mums usually wear something very formal and dark coloured. I might tactfully suggest that she might find all that fabric very hot in Spain in August and say that the wedding isn’t black tie so she’s welcome to wear something floatier/less formal, for her own comfort!

Really bizarre choice for her but you may have to suck it up if that's what she wants!

Yes I think she may be signalling how she really feels about the marriage 👀🫣

Post the dress so we can see

Fantastic.

Will she wear a mantilla as well op?

It is in Spain after all...😁

A black dress worn by a MIL is not fine.

Is she trying to look like a Flamenco dancer? Mistakenly thinking it goes with your theme?

Having had my own wedding, and been a guest at many, the worst thing you could hope for is everyone to look amazing and for the day to go off without a hitch.

If that happens, your wedding will then blend into every other highly curated, over produced wedding, and all you hard work ends up in a catalogue of "gosh, I don't really remember".

You want people, individuals at your wedding. A few mad dresses, a wild hat or three, something to go wrong, and a lot to go right.

Most of the great reminiscing we do in life Is over the human failures and how life proceeded anyway.

Let your mother in law be herself. Don't ask her to be.

And really remember this; without guests you have no wedding party. If all those people you invite did not spend their hard earned time and money on you and for you, you would not be able to celebrate. So celebrate your guests. Be grateful.

I often think OPs concerning guest's outfits are a bit Bridezilla...not in your case. No MOG buys a dress like that unless it's to send a very clear message that she's in mourning.

Black dress is fine in 2025 (if a bit warm in Spain) but a train.....😂

I think I'd just treat this as an obvious joke "black dress is ok but never seen anyone except the bride wear a train at a wedding, are you winding me up? 😂"