Systems and methods for determining seller reputation for users of an online gaming platform are disclosed. Exemplary implementations may: execute an instance of the game; monitor sales transactions; determine a sales metric that represents a sales reputation ascribed to a given user; monitor in-game actions of the given user that do not include sales transactions; determine in-game action metrics for the monitored in-game actions; and determine a combined reputational score based on the sales metric and the in-game action metrics.