Stock adapters for firearms have a first adapter portion having a firearm interface configured to removably connect to the stock interface of the firearm, the first adapter portion having a quick detach first adapter interface, a second adapter portion having a stock interface configured to removably connect to the firearm interface of the stock, the second adapter portion having a quick detach second adapter interface configured to removably connect to the firearm interface of the stock, and the first and second adapter interfaces being removably joined in an abutting condition, and when in the abutting condition relatively rotatable between an unlocked condition in which the first and second adapter interfaces are axially separable, and a locked condition in which the first and second adapter interfaces are axially inseparable. The first and second adapter interfaces may be rotationally aligned to rotationally interface about the barrel axis.