The league announced Wednesday that Wallace was fined $5,000 for picking up his second flopping violation of the season late in the third quarter of Saturday night's 102-89 loss to the Miami Heat.
Wallace exaggerated contact and fell to the floor while guarding LeBron James in order to draw a charge as James began to drive to the basket with 51.8 seconds left in the third.
Wallace picked up his first warning for a flop in the Nets' 96-89 overtime victory Nov. 26 over the New York Knicks.
Two weeks ago, Nets power forward Reggie Evans became the first player in league history to be fined for flopping.
Wallace's next violation would result in a $10,000 fine. A fourth violation would result in a $15,000 fine, a fifth $30,000, and six or more could lead to a suspension.
Mike Mazzeo is regular contributor to ESPNNewYork.com