A split decision (SD) is a winning criterion in boxing, most commonly in full-contact combat sports, in which two of the three judges score one particular competitor as the winner, while the third judge scores for the other competitor.
A split decision is different from a majority decision. A majority decision occurs when two judges pick the same competitor as the winner, and the third judge scores the contest a draw (tie). The official result remains the same in both split and majority decisions, but the margin of victory is greater in a majority decision and less in a split decision.
Occasionally, the judges' final decision is a tie, because the first judge scores for one competitor, the second one scores for the other competitor, and the third judge scores the contest a draw (tie); so in this case the official result is a split draw.
Often, a split decision causes controversy due to its lack of unanimity. As a result, especially in high-profile or title fights, the victor may be encouraged or pressured to grant a rematch, in the hopes a return match-up will have a more decisive outcome.