Happy Nightmare Baby is the only studio album by the American band Opal, released in 1987 by SST Records in America and Rough Trade Records in England.

[1] It was the only album released by the band while together, singer Kendra Smith leaving during the tour to promote it, to be replaced by Hope Sandoval, the band evolving into Mazzy Star.

"[4] Ned Raggett, reviewing the album for AllMusic, called it "at once drowsy, psychedelic, entrancing, and possessed of a sinuous spark".

[3] Trouser Press described Smith's singing as "laconic", some of the instrumentation as "self-indulgent nonsense" and the pace as too slow, but viewed the album as "ultimately satisfying".

[5] Andrew Earles, in his book Gimme Indie Rock: 500 Essential American Underground Rock Albums 1981-1996 described the album as "Velvet Underground meets T-Rex at the intersection of proto-shoegaze and neo-psychedelia".