Are gambesons worn under or over armor?

A gambeson could be worn in conjunction with mail and/or plate (in which case it was often known as an aketon), or as stand-alone armour. read more

You never wore a gambeson under (with maille you wear it under) or over. It is a piece that is designed to be a seperate piece of armour often 30–32 layers thick. read more

A gambeson (also aketon, padded jack or arming doublet) is a padded defensive jacket, worn as armour separately, or combined with mail or plate armour. It also doubled as a winter coat for wearers. Gambesons were produced with a sewing technique called quilting. read more

Here he is wearing what you wear when you start getting fancy : an arming greatcoat. Note the voluminous sleeves and fancy fabrics. It’s essentially a version of a nobleman’s houppelande meant to be worn with armour and to allow sufficient mobility to fight. read more