Courtenay (/ˈkɔːrtni/ KORT-nee) is a city of 28,420 on the east coast of Vancouver Island, in the Canadian province of British Columbia. It is the largest community and only city in the area commonly known as the Comox Valley, and the seat of the Comox Valley Regional District, which replaced the Comox-Strathcona Regional District. Courtenay is 4 km (2.5 mi) west of the town of Comox, 7 km (4.3 mi) northeast of the village of Cumberland, 5 km (3.1 mi) northwest of the unincorporated settlement of Royston, and 108 km (67 mi) northwest of Nanaimo.

It was named after the nearby river, Courtenay River, which in turn had been named for Rear-Admiral Courtenay.

Courtenay and nearby Comox are served by the coast-spanning Island Highway, the Island Rail Corridor, and a local airport in Comox.

Archaeological evidence suggests there was an active Coast Salish fishing settlement on the shores of the Courtenay River Estuary for at least 4,000 years. Due to its gentle climate, fertile soil and abundant sea life, the Coast Salish residents called the area kw'umuxws (Li'kwala for plentiful), which was eventually anglicized to Komoux and then to Comox.

At the time of first contact with Europeans, the Pentlatch Nation, who spoke the Pentlatch language of the Coast Salish family, occupied the shores of present-day Comox Bay. (The last speaker of the Island Comox dialect died in 1995.) Another Island Comox speaking Nation, the K'ómoks, occupied settlements further north along the east coast of Vancouver Island, in the area of present-day Campbell River, including Quadra Island and several other Gulf islands.

Along the tidal flats of the estuary, the Pentlatch set out elaborate fishing weirs—nets tied to wooden stakes that would be covered at high tide but uncovered at low tide, allowing trapped fish to be removed. These wooden stakes can still be seen at low tide — local archaeologist Nancy Greene has estimated that up to 200,000 wooden stakes remain in the mud flats. Several of these wooden stakes were carbon dated, revealing the oldest to be made from a hemlock tree c.750 CE, while the youngest dated from around 1830. Some scientists estimate that the weirs could have supported a population of several thousand people. The Pentlatch also harvested the abundant shellfish in Comox Bay.

By the 19th century, the K'ómoks had been driven out of their lands near Campbell River by the Lekwiltok, a particularly fierce group of Kwakwaka'wakw. The K'ómoks migrated south to the shores of the Courtenay River estuary, where they allied with the resident Pentlatch against their common enemy. In 1862, a major smallpox epidemic swept across Vancouver Island, killing an estimated 30% of First Nations people. A census of First Nations in the Comox Valley taken in 1876 revealed that the local First Nations population had dwindled to only 88 K'ómoks and 21 Pentlatch.

European settlers began to arrive in the area in 1872, and by 1876, the K'ómoks and Pentledge had been moved onto two reservations: Comox Indian Reserve No. 1 adjacent to the village of Comox, and Pentledge Indian Reserve No. 2 at the confluence of the Puntledge and Tsolum rivers adjacent to the village of Courtenay.