His strong form in Scotland attracted attention from south of the border and McAvennie had talks with Luton Town and their manager, David Pleat, in the summer of 1985. With talks progressing well McAvennie decided not to sign for Luton due to the attitude of their chairman, David Evans. With St Mirren then agreeing a fee with West Ham United, McAvennie met with their manager John Lyall and his staff and he signed for them in June 1985 for £340,000. He made his West Ham debut on 17 August 1985, the opening game of the season, in a 1-0 away defeat to Birmingham City with his first two goals coming in his second game, a 3-1 home defeat of Queens Park Rangers. Originally signed as an attacking midfielder he was played as an out-and-out striker after an injury to Paul Goddard in the opening game of the season. He would go on to keep Goddard out of the team and spark his transfer from the club the following season.