Abstract: A ball valve comprises: a valve body; a pair of valve end caps; a valve ball rotatably positioned within the valve body; a pair of valve seats, each valve seat being positioned between the valve ball and a respective valve end cap and engaged therewith; and at least one of i) an O-ring in an outer circumferential groove on a valve seat and compressively engaged with an inner surface of the valve end cap for retaining the valve seat within the end cap, ii) a circumferential groove provided on an inner surface of the valve end cap and positioned for receiving the O-ring positioned within the groove of the valve seat for retaining the valve seat within the end cap, and iii) an inwardly-extending circumferential flange provided on an inner surface of the valve end cap and positioned for retaining the valve seat within the end cap.