Coming off a 50-point outburst against Chicago on Friday night, Embiid had 25 points and 17 rebounds for the 76ers, who lost their fourth consecutive road game.
The 76ers led 55-52 after an 18-point first half by Simmons, who had missed two games with a stomach virus after scoring 42 points in a loss at Utah.
Philadelphia shot 39% for the game.
76ers: G Shake Milton played 29 minutes after missing five games with a left ankle injury.
76ers: Play the Raptors again Tuesday night in Tampa before four straight home games.