The Ontario Association of Certified Engineering Technicians and Technologists (OACETT) is a non-profit, self-governing regulatory body and professional association of over 21,000 members.

OACETT is Ontario's independent certifying body for engineering and applied science technicians and technologists and confers the certifications C.Tech. (Certified Technician) and C.E.T. (Certified Engineering Technologist). These certifications are recognized across Canada by employers and other engineering professionals. The A.Sc.T. (Applied Science Technologist) designation is no longer conferred but is still used by some OACETT members.

OACETT promotes the interests of engineering and applied science technicians and technologists in industry, educational institutions, the public and government. OACETT was incorporated in 1962 and legislated under the Statutes of Ontario by the OACETT Act of 1984. The Act established OACETT as a self-governing body with right to title for its members. The provincial legislature passed the OACETT Act of 1998, a revised act that includes a description of work for technicians and technologists.

While the OACETT Act establishes the association as a self-governing body, By-law 20 sets out how the association operates, defining all aspects of its governance.

The Association’s Code of Ethics and Rules of Professional Conduct outline for members of the association the precepts of personal integrity and professional competence.

Engineering technicians and technologists are part of the engineering team that also consists of engineers, scientists and tradespeople. Each performs an integral part of engineering work.