Think tanks are not government agencies, but they typically comment on, and seek to influence, public policy, so I've included info on them in this guide.
A think tank is an interdisciplinary body of experts such as scholars or former politicians that crafts opinions on regional, national or international policy and strategic direction, typically related to areas such as commerce, the military, immigration or social welfare. Often independent, some think tanks are known for certain political leanings and their reports and findings are interpreted accordingly.
Yusufali, Sasha. "Think Tank" in Canadian Encyclopedia.
The University of Toronto Library has a helpful guide to Canadian and international think tank resources.
Most think tanks freely publish their reports on their websites. Some charge for their publications. It can be cumbersome to search many different websites for information on a particular topic, so you may want to try the following tools:
According to the 2020 Global Go-To Think Tank Index (GGTTTI, see note 1), these are the top 10 Canadian think tanks:
Fraser Institute: Centre of Excellence (see note 2)
Source: 2020 GGTTTI Table # 5, "Top Think Tanks in Mexico and Canada", pp. 81-83.
Note 1: The Think Tank and Civil Societies Project that produced this Index ceased in 2021. The 2020 index was the last one produced.
Note 2: The Fraser Institute -- which had been ranked #1 for many years running -- has been singled out as a "Center of Excellence, 2017-2019" for the region of Mexico and Canada.