5.11 does not specify.
5.11 does not make women's specific tactical boots, but you should be able to do a size conversion from men's to women's. A Women's Size 8.5 would convert to a Men's Size 7, so you could give those a try if you like. If you get them and they don't fit, our return/exchange process is pretty painless.
If you typically wear size 11.5 M, I would suggest starting there. If you get them and they don't fit, our return/exchange process is pretty painless for you to exchange them for a different size.