Product testing also called consumer testing or comparative testing, is a process of measuring the properties or performance of products.The theory is that since the advent of mass production manufacturers produce branded products which they assert and advertise to be identical within some technical standard.

Product testing seeks to ensure that consumers can understand what products will do for them and which products are the best value. Product testing is a strategy to increase consumer protection by checking the claims made during marketing strategies such as advertising, which by their nature are in the interest of the entity distributing the service and not necessarily in the interest of the consumer. The advent of product testing was the beginning of the modern consumer movement.

Product testing might be accomplished by a manufacturer, an independent laboratory, a government agency, etc. Often an existing formal test method is used as a basis for testing. Other times engineers develop methods of test which are suited to the specific purpose. Comparative testing subjects several replicate samples of similar products to identical test conditions.