Sterling missed a number of clear chances during the 2-0 victory, which saw England reach the semi-finals of a World Cup for the first time since 1990.
Despite the team's success, the 23-year-old's individual performance was heavily criticised in some quarters, but Beckham has come to the defence of the Manchester City winger.
"Haven't seen this but whatever it is it's wrong," Beckham posted in an Instagram story.
"We are in the semi-final of a World Cup. Every player deserves to be applauded. We as a country are united and behind the team."
England will face Croatia in the semi-final on Wednesday night.