On 12 January 2011, Bentley joined Birmingham City on loan for the remainder of the season. He went straight into the starting eleven for the Second City derby against Aston Villa and was named man of the match. Bentley scored his first goal for Birmingham in a 3–2 win against Coventry City in the fourth round of the 2010–11 FA Cup. Bentley was cup-tied for Birmingham's victory in the 2011 League Cup Final. Described in the "Birmingham Mail"'s season review as having "flattered to deceive", he failed to establish himself in the first team, and returned to Tottenham at the end of the season.