First recorded by The Vogues (1968).
Also recorded by Leonard Nimoy (1968), Pierre Lalonde (1968), The Will-O-Bees (1969).
Hit version by “Mama” Cass Elliot (US #30/MOR #13/UK #8 1969).
From the wiki: “‘It’s Getting Better’ was written by Barry Mann and Cynthia Weil (‘Make Your Own Kind of Music‘,’Never Gonna Let You Go‘, ‘We Gotta Get Out of This Place‘). The earliest evident recording of ‘It’s Getting Better’ was by the Vogues for their August 1968 album release Turn Around, Look at Me for Reprise Records. Also in 1968, the song was featured on the Leonard Nimoy album The Way I Feel released that October. The first evident single release of ‘It’s Getting Better’ was by French-Canadian singer, Peter Martin (born Pierre Lalonde), in September 1968.
“The folk-rock and sunshine pop trio, The Will-O-Bees, released ‘It’s Getting Better’ as a single in early 1969 but it failed to chart. (The group had also been among the first to record ‘Make Your Own Kind of Music‘, in 1968, previous to Cass Elliot’s hit recording.)
“‘It’s Getting Better’ was covered by Cass Elliot for inclusion on her June 1969 album release Bubblegum, Lemonade, and … Something for Mama. The Wrecking Crew (James Burton on guitar, Hal Blaine on drums, Larry Knechtel on keyboards, and Joe Osborn on bass) — who’d regularly backed The Mamas & the Papas — were among the instrumentalists on the album. Cass’ arrangement peaked at #30 in August 1969 during what was then considered an unusually lengthy 19-week run on Billboard’s Hot 100. Only five other 1969 releases had longer chart runs on the Hot 100. Elliot’s ‘It’s Getting Better’ had a more pronounced chart impact in the UK, reaching #8 in October 1969.”