Defence Research and Development Canada (DRDC; French: Recherche et développement pour la défense Canada, RDDC) is the science and technology organization of the Department of National Defence (DND), whose purpose is to provide the Canadian Armed Forces (CAF), other government departments, and public safety and national security communities with knowledge and technology.

DRDC has approximately 1,400 employees across seven research centres within Canada.

After the First World War, national research and development in Canada was organized under the National Research Council (NRC). The NRC was founded in 1925 based on a wartime British recommendation to establish military laboratories in Canada, but by that time the main priorities were developing domestic university and industrial research and civilian projects. Greater interest in military applied research arrived in 1935 when Major-General Andrew McNaughton became President of the NRC. In the period before the Second World War, the NRC undertook research in radar, aviation medicine, artillery, aircraft, gas masks, and metallic magnesium production. Chalmers Jack Mackenzie became acting President at the onset of the Second World War when McNaughton assumed an operational command within the Canadian Army, formally succeeding McNaughton in 1944.

Following the fall of France in June 1940, the NRC assumed control of all Canadian scientific research and became responsible for applying it toward military applications. Laboratories and facilities were established by the NRC and the Canadian Armed Forces; biological and chemical warfare laboratories cooperated closely with Allied counterparts.

In 1944, Chalmers Mackenzie and the armed forces began considering the issue of post-war military research, and concluded that a separate military research organization was required. The result was the creation of the Defence Research Board (DRB) within the Department of National Defence (DND) in April 1947, which took over coordinating defence research from the NRC and advising DND on scientific matters. The overall organization of defence research continued to mimic the NRC. The DRB was—as envisioned by proposals in 1945—an interim solution; creating an organization within DND required minimal political action compared to creating a new government department that would subsume both the NRC and defence research. Omond Solandt was the first Chairman of the DRB. The DRB received seven existing NRC facilities.

The DRB was the last part of DND to adapt to the unification of the Canadian Armed Forces of 1968. DRB began transitioning to the new structure in 1974, and dissolved in 1977. Six of the seven DRB research establishments were transferred to the newly created Defence Research and Development Branch (DRDB) of the Canadian Armed Forces (CAF).

In the 1990s, budget cuts and the complexity of greater reliance on cheaper contracting drove a review of the organization of defence research. In 2000, the DRDB was replaced by Defence Research and Development Canada (DRDC) which was–like the DRB before–a DND agency.

Located in Halifax, Nova Scotia, the Atlantic Research Centre conducts research and development activities related to the maritime defence and security domains, but also to the air and land environments. The Centre traces its formation to 1944 when it was established as the Defence Research Establishment Atlantic (DREA) by the Royal Canadian Navy. DREA was one of the originating organizations that came together in 1947 to form the Defense Research Board which later became DRDC.