Zinc Alloy and the Hidden Riders of Tomorrow is an album by English rock band T. Rex, the ninth since Tyrannosaurus Rex's debut LP. It was released in March 1974 on the T.Rex record label, distributed by EMI. It was the first and only album to be released under the moniker "Marc Bolan & T. Rex".

T. Rex were an English rock band, formed in 1967 by singer-songwriter and guitarist Marc Bolan, who was their leader, frontman and only consistent member. Though initially associated with the psychedelic folk genre, Bolan began to change the band's style towards electric rock in 1969, and shortened their name to T. Rex the following year. This development culminated in 1970 with their first hit single "Ride a White Swan", and the group soon became pioneers of the glam rock movement.