The Battle of Mulleriyawa (Sinhalese: මුල්ලේරියාව සටන) in 1559 was a battle and a part of the Sinhalese–Portuguese War. It was one of the most decisive battles in Sri Lankan history and considered as the worst and most devastating defeat of Portuguese during that period. According to local chronicles the marshlands of Mulleriyawa turned red with blood after the annihilation of the Portuguese. With this victory Sitawaka emerged as a military power which able to challenge the Portuguese expansion.