Need help asserting myself with my resignation from a committee I'm on

The shorter the better.

That makes points without you having to.

Exactly this. Be the bigger person in your formal communication. Save the red mist for if/when they ask you why.

"Dear X

Please accept this as my resignation. Effectively immediately."

And if the lead person reaches out for more information "Honestly I found your behaviour and attitude intolerable"

How about you resign and then have a chat with the person you feel disrespected by face to face.
Always make me feel better.

I would suggest that you firstly make sure that it goes straight to the whole committee - that way you cannot be misrepresented to the entire committee.

I remember when dh had offered to stay on a committee that he had done a lot of work for, and assist with setting the next couple of months afterwards, because things were going rather badly wrong and the experienced people had all stepped down. The night before the next meeting (at about 10pm) he got a message from the chair (with whom he'd discussed it with and asked him to stay only the previous week) who said that he thought it was inappropriate for him to stay on so as he was only staying to try and give the chair a fair chance to get this done, he agreed.
In the meeting the next day it was phrased by the chair "Mr Thursday has resigned. He left it until 10pm last night to tell me, which has left me with no time to fill the gap...."

I'd also say from the point of view of having been there, I think if you can potentially cope with the potential fallout, make sure that it is clear that it is due to one particular person.
Having been the fifth person to resign directly due to a specific person (and several more mostly due to them), it was frustrating to be told that no one else had a problem with them. If everyone had been honest, then something would have had to be done which would have been far better for the group.
It would have also given the people who were in the position of considering resigning potential leverage to say that there was an issue. As it was everything continued as "normal" and more people resigned leaving a very empty hole.

But keep it from being emotional. Keep it factual as much as possible, and ideally make sure you have examples (if you have physical proof or witnesses even better) for each.

I like this!

I was on a committee where another member badgered me so much that he was pestering me to write emails in his behalf on Easter Sunday. I resigned immediately . I first emailed the rest of the committee a polite message to say I was resigning from that moment and then I replied to the bully (a male misogynist) that I couldn't fulfil his request as I was no longer a committee member.
i didn't say any more than that I was resigning and gave no reasons. However everybody knew why I'd left . And although he and his wife suddenly changed their behaviour towards me and begged me to go back I refused .
I'm still able be on good terms with that community .

I'm on a different committee now and people do moan and make mad suggestions , I find that the best way to deal with them is to say yup, good idea would you like to do it, they soon disappear and I carry on with my task in hand , but I'd be more than happy to let someone else take over, should they wish .
in other words resign , don't complain , don't explain . Your fellow committee members will know the score .

You are a volunteer. You aren't resigning from an official position. There is no contract, nor any penalties for leaving early.

You're stepping down from a voluntary position on a committee. There is no obligation to stay for a specific term. You can leave with no notice at all and whenever you like. You don't have to say why, and if anyone asks, just say you don't want to do it any more.

This is perfect. It is brief, factually accurate and free of all emotion. It is more than sufficient.
Never, ever put personal or emotional content in a resignation letter - it just makes the writer look bad.

I've been on and off a variety of committees over the years. You don't have to 'resign' from a voluntary committee position. You just tell them you are stepping down from your position on whatever date.

"Dear Chairperson,
Project X has now come to a conclusion. After long and careful consideration, I have therefore decided to step down from the committee of Organisation with immediate effect. With kind regards, FlyBy."

Don't say any more than that. It really isn't needed. Generally speaking, people tend to do it immediately before the AGM, but you don't have to do that.

Respectfully, it isn't the OP's job to provide people who mistreated her with feedback. If they're concerned about why she resigned, they are of course free to write to her and ask her about her reasons.

As someone whose job involves supporting a lot of committee volunteers, something in the middle would be useful from my POV. People can’t improve if they don’t know the real reason you’re stepping down - there’s a polite but firm way to get your point across.

I would structure as: I am resigning, last meeting will be x date blah blah

I’d like to give some constructive feedback. I have volunteered a lot of time to this project and have often felt disrespected. It is the right time for me to stand down now but I wanted to feed back on my volunteer experience”

Dear Chair,
I resign my position as your whipping boy or (whatever it was) with effect from Friday, February 6th. I shall send my clubhouse keys to you by courier from that date.
I wish the disrespectful asshole committee success in its future projects,
Regards
FlyBy

You've had some good advice, OP. It's amazing how often this voluntary committee work can be such a poison chalice. I used to be on my local residents committee. We dealt with a range of very varied issue affecting the area. At that time I was a keen cyclist. There were two women on the committee who were keen horse riders. Every time we gathered in our meeting room, waiting to start, these two horse riders would talk very loudly about what awful people cyclists were, with the full knowledge that I was a cyclist. What bullies! I handed in my notice because I thought there was absolutely no point in complaining because they were very well respected on the community and rather wealthy. They used to do things like hold coffee mornings for the elderly. It's a shame that people feel the need put others down.

Yes, but going on about how furious you are and complaining about your treatment in your resignation letter isn't 'assertive', it's the classic thing that unassertive people or people-pleasers do -- they don't actually assert themselves in the role, or communicate clearly with whoever is exploiting them, they seethe with silent resentment and bottle it up until they explode when it's far too late to do them any good.

What @FavouriteBlueMug said, for future reference. But telling them why you're resigning isn't going to do you any good at all, or magically make you assertive. Just send a frostily professional email, and be done with it. And ask yourself why you keep allowing yourself to be treated like shit in voluntary roles. Take an assertiveness course.

Is this the golf committee?

Please don’t send this. It demeans you.

I know this feeling! Voluntary committees, subcommittees, projects etc can be verrrrrry challenging and have been much harder people wise than anything I've ever experienced in my professional life.

Don't say what you plan to. I get why you want to but save it for another day.

Once your project is completed, resign, step back. Be gracious and classy and thank everyone who was part of the success of the project.

Something more like: "As the x project has come to a close, it feels the right time to step away from the role and committee. I'm proud of what we've been able to achieve and I hope that the community continues to benefit from the work of the committee."

Don't make it personal. Don't make it about them.

Of course, you're free to word of mouth your relief to whoever you want but keep emails and meetings and letters professional and rise above. This person sounds like they'll drive other people away which is to the detriment of whoever should benefit from the committee's activities.

It its harder to quit a voluntary role on a committee than a job.

No it isn't. You won't lose salary over it, you needn't worry about references or any of the other life effects of leaving a job. Just say that you have decided to resign your position and, additionally, leave the organisation. You can either say "with immediate effect" or "my final day will be xxx" then "yours sincerely" and the job is done. You might like to add that you will of course delele any relevant documents, emails, contact details and so on from any personal equipment that you may own, and request that they delete your details and personal information from their database.

I agree with other PP's who advocate a short, formal announcement; nothing to come back and bite you. Keep it sparse on detail, leave them wondering.
However, if it makes you feel better, you could draft the version where you give both barrels, chapter and verse, being as petulant as you like.
Then print it off and shred it, jumping up and down on the pieces if it helps, or burning it.
At report-writing time, I would sometimes draft the scurrilous, warts and all version of what I would like to say, which was then destroyed; I found it lightened my spirits.
Console yourself with the image of the oncoming dilemmas they will face, without you to clear up the mess, reluctant to admit to themselves that it is their loss that you were unappreciated.

Yes I've linked above.

https://www.mumsnet.com/talk/am_i_being_unreasonable/5470622-i-feel-down-about-the-hobby-i-took-up

This one @FlyBy2026

If it's you. Please leave them.

I was thinking of a different thread where OP was feeling used by people and spending a huge amount of time on a project for the committee. They treated her really badly and took her for granted. I believe she struggled to say 'no' and with assertiveness.

Absolutely agree with keeping it to the facts of resigning. If you feel you need to add anything like a reason, something like, "I've been re-evaluating my commitments for the upcoming year and I needed to cut back on voluntary roles."

I think you can tell anyone who asks you in person an unemotional version of the truth: that you felt your contributions weren't valued, that you were treated poorly, and that you'd rather give your time and efforts elsewhere.

There was a similar thread fairly recently involving golf I think?

My tip for dealing with awful people is to be incredibly nice. They have no idea what to do with that (and they can’t quote or bad mouth you).

so I’d say - ‘as the x project is coming to an end I’d like to let you know that my last day is x. It has been such a pleasure creating this together and I wish you well with the rest of this years plans.’

it will blow their petty minds