The Battle of Mullaitivu (Tamil: முல்லைத்தீவுப் போர், romanized: Mullaittīvup Pōr; Sinhala: මුලතිව් සටන Mulativ Saṭana), also known as the First Battle of Mullaitivu and codenamed Operation Unceasing Waves (Tamil: ஓயாத அலைகள் நடவடிக்கை, romanized: Ōyāta Alaikaḷ Naṭavaṭikkai), was a battle between the militant Liberation Tigers of Tamil Eelam (LTTE or Tamil Tigers) and the Sri Lankan military during the Sri Lankan Civil War for control of the military base in Mullaitivu in north-eastern Sri Lanka.

The base was overrun by the LTTE on 18 July 1996 and, after a failed rescue operation involving all three forces, the Sri Lankan military abandoned the base, and control of much of Mullaitivu District, to the LTTE on 25 July 1996. Around 1,400 Sri Lankan troops were killed and large amounts of military equipment captured by the LTTE. Around 330 LTTE cadres were killed.