First recorded by Jimmy Cliff (1970, released 1976).
Hit versions by The Pioneers (UK #5 1971), Brownville Station (US #57 1973).
From the wiki: “‘Let Your Yeah Be Yeah’ was written by Jamaican singer Jimmy Cliff who first recorded the song in 1970 but which went unreleased until 1976.
“Vocal trio The Pioneers recorded their version, co-produced by Cliff, in 1971. It peaked at #5 on the UK singles chart. In 1973, ‘Let Your Yeah Be Yeah’ was recorded by the US rock band Brownsville Station (‘Smokin’ in the Boy’s Room’) for their album Yeah!. Released as a single, it was the band’s second song to chart on the Billboard Hot 100, reaching #57.”