I am looking for Gulutein Flour in Bangkok.

"Gluten flour is wheat flour made with the bran and starch removed. Low in carbs and very high in protein"

Does any one know where to buy them?

Usually it's called "wheat gluten" not "gluten flour". I"m not being picayune here, but if you go asking for "gluten flour" you might just confuse the locals. In Chiang Mai I can get it at the baking supply houses and sometimes at Rimping supermarket. I'm assuming that Bangkok has its own baking supply houses and upscale supermarkets like Rimping that stock western baking supplies.

Thank you for the information.