Rabaul is a township in East New Britain province, Papua New Guinea. The town was the provincial capital and most important settlement in the province until it was destroyed in 1994 by falling ash of a volcanic eruption. After the eruption the capital was moved to Kokopo, about away. Rabaul is continually threatened by volcanic activity due to being built on the edge of Rabaul caldera, a flooded caldera of a large volcano.

Rabaul was the headquarters of German New Guinea until captured by the British Commonwealth during World War I, when it became the capital of the Australian mandatory Territory of New Guinea until 1937. During World War II it was captured by the Japanese in 1942, and it became the main the base of Japanese military and naval activity in the South Pacific. Settlements and military installations around the edge of the caldera are often collectively referred to as Rabaul despite the old town of Rabaul itself being reduced to practical insignificance by the volcanic eruption in 1994.

As a tourist destination Rabaul is popular for SCUBA diving and for snorkelling sites and a spectacular harbour; it had been the premier commercial and travel destination in Papua New Guinea and indeed in the wider South Pacific during much of the 20th century until the 1994 volcanic eruptions. There are still several diving operators based there.