A demountable wall system includes similarly configured channel segments having a hat-shaped center, a pair of center flanges, and L-shaped outer ends with fastener portions formed therein. A rigid stud having an I-shaped plan configuration is formed from a pair of the channel segments interconnected in a back-to-back relationship, wherein adjacent end flanges form outer stud faces against which wall panels are supported, and adjacent fastener portions form connector channels in which the wall panels are detachably retained. A header/footer track is formed from a channel segment connected with a flat base strip, and is attached to the opposite ends of the stud by stud extenders to define a frame on which the wall panels are supported.