Outaouais (/uːtəweɪ/, French pronunciation: [utawɛ] ^ⓘ; also commonly called The Outaouais) is an administrative region of western Quebec, Canada. It includes the city of Gatineau, the municipality of Val-des-Monts, the municipality of Cantley and the Papineau region. Geographically, it is located on the north side of the Ottawa River opposite Canada's capital, Ottawa. It has a land area of 30,457.52 square kilometres (11,759.71 sq mi) and its population was 405,158 inhabitants as of 2021.

From 2017 to 2021, the Outaouais has a lower per capita disposable income than the rest of Quebec. It was $32,364 in 2021, compared to $34,180 in Quebec overall. In 2021, the unfavourable margin remained stable at 5.3%.

The name of the region comes from the French name for the Ottawa River, which in turn comes from the French name for the Indigenous Odawa that lived near the region. Prior to European arrival in the region, the areas along the Ottawa River were commonly used by various tribes to trade and gather.

The oldest European settlement in the region is Hull (now a neighbourhood of Gatineau) which was founded in 1800 by Philemon Wright as Wright's Town. The settlement quickly became involved in the lumber trade, which continued along the Ottawa River until the late 20th century. None of the original town buildings remain today, as they were destroyed in the 1900 Hull–Ottawa fire. Hull remained a city until 2002, when it was merged with several neighboring cities to form the current city of Gatineau.

For the next few years, the Outaouais is predicted to enjoy continuous demographic increase.

From 2021 to 2026, the region's population is predicted to expand faster than the rest of Quebec (+4.8% against +4.2%).

Longer-term projections show that the region's population will expand faster than Quebec's for each following five-year period.

Year after year, the Outaouais' net migration (inflows minus outflows) with other areas is positive.