The Ontario Securities Commission (OSC) is a regulatory agency overseeing securities trading in the province of Ontario in Canada. It is the largest such regulatory agency in Canada, as it oversees the highly active Toronto Stock Exchange. This organization cooperates with a number of related regulatory agencies, including other provincial and territorial regulatory organizations belonging to the Canadian Securities Administrators, a group of securities regulators in Canada. Like other securities regulators around the world, it promotes fairness and efficiency in the markets while protecting investors.

This organization is empowered by the Securities Act (Ontario), a piece of legislation denoting the scope of the Ontario Securities Commission's authority. It is allowed to sponsor and assist self-regulatory agencies from within the securities community, as well as creating, implementing, and enforcing policy. It can audit suspect companies and individuals and take other actions to enforce regulation of trades, sales, exchanges, quotation and trade reporting systems, and alternative trading systems used in Ontario.

Protection of investors is an important aspect of the work of the Ontario Securities Commission. Promoting investor confidence and ensuring that markets remain fair and accessible is another component. The organization also works to keep the market strong and in cooperation with other organizations, keeps the Canadian economy growing sustainably to both attract foreign investment and keep domestic investors feeling confident in the market.

Changes in the financial industry result in corresponding needs for adjustments at the Ontario Securities Commission. Regulatory changes are passed in response to the development of new trading tactics, as well as new trends in the securities industry. Monitoring people active in the industry for signs of fraud and other unscrupulous activity is a full-time job for this organization and the large staff it employs to watch the markets, conduct audits, and educate the public about securities issues.

People with experience in the financial industry can seek employment at the Ontario Securities Commission, as can people like attorneys, accountants, and civil servants. Job offerings arise with the organization on a regular basis and many positions include a number of benefits designed to keep people working with the organization. People interested in lifetime careers as employees of the Ontario Securities Commission can access employment incentives and have an opportunity for advancement within the organization. Job requirements vary, depending on the nature of an opening and information about prerequisites is usually provided in job listings for the convenience of job seekers.