Peter John Kay was born on 2 July 1973 in Farnworth, Lancashire, where he attended Mount Saint Joseph School, leaving with a GCSE in art.
His father, Michael, was an engineer who died just before Peter's career took off. His mother, Deirdre (née O'Neill), is an Irish Catholic originally from Coalisland, County Tyrone, and Peter was brought up in her faith.
Kay took several minor jobs, including working in a toilet roll factory, a Netto supermarket, a video rental shop, Manchester Arena, a cash-and-carry, a cinema, a petrol station and a bingo hall, which later inspired episodes for That Peter Kay Thing. He was sacked from each, after a few months, for "not taking things seriously".
Kay began a degree course at the University of Liverpool in Drama, Theatre Studies and English Literature. He had misinformed the university to accept him, telling the university that he had four GCSEs and A-levels in Psychology and English Literature. Struggling with the course, he changed to studying a Higher National Diploma (HND) in media performance (including stand-up) at the University of Salford's Adelphi Campus School of Media, Music and Performance. In recognition of his contribution to the entertainment industry, Kay received an honorary Doctor of Arts degree from Salford University on 19 July 2016, at Salford's Lowry Theatre.