Cineplex Inc. (formerly Cineplex Entertainment and Cineplex Galaxy) is a Canadian operator of movie theatre and family entertainment centres, headquartered in Toronto. It is the largest cinema chain in Canada; as of 2019, it operated 165 locations, and accounted for 75% of the domestic box office.

The company was formed in 2003 via the acquisition of Loews Cineplex's Canadian operations (which included the assets of the former Cineplex Odeon chain) by Onex Corporation and Oaktree Capital Management, and its subsequent merger with Onex's Galaxy Entertainment—a chain of cinemas that was established in 1999 by former Cineplex Odeon executives, and operated primarily in smaller markets. The company subsequently acquired Famous Players from National Amusements in 2005, went public in 2011, and acquired Empire Theatres' operations in Atlantic Canada and parts of Ontario in 2013. In December 2019, Cineplex agreed to be acquired by British exhibitor Cineworld Group for $2.8 billion, pending regulatory and shareholder approval, but Cineworld abandoned the sale in June 2020 due to unspecified breaches of the sale terms.

The company operates cinemas across Canada, primarily under the brand Cineplex Cinemas. Some flagship locations operate as Scotiabank Theatre, while some locations use brands carried over from its corporate predecessors (such as Famous Players, SilverCity, Odeon, and Galaxy, although some of them have since been converted to the Cineplex banner). The company also owns family entertainment centres under the brands The Rec Room and Playdium, the rewards loyalty program Scene+ (in partnership with Scotiabank and the Empire Company), the e-commerce Cineplex Store, film distributor Cineplex Pictures and the digital advertising business Cineplex Media.

Cineplex stakes a partial claim to the history of the Famous Players Film Company (later Paramount Pictures), founded in 1912 by Adolph Zukor, as Cineplex's earliest predecessor; however, that company did not have any operations in Canada until 1920, when it bought Nathan Nathanson's Paramount Theatre chain, which Nathanson had established four years earlier. Nathanson, the 5th richest person in the world, became the first president of the resulting entity, Famous Player Canadian Corporation. In 1923, Famous Players bought out rival Allen Theatres, acquiring many buildings in the process.

Odeon Theatres of Canada was established in 1941, before merging with the Canadian Theatres chain in 1978, becoming Canadian Odeon Theatres.

In 1979, Garth Drabinsky and Nat Taylor created the Cineplex Corporation and opened its first "Cineplex" theatre complex, in the Toronto Eaton Centre. Odeon merged with Cineplex in 1984 to form Cineplex Odeon Corporation, before being acquired by Loews Theatres in 1998, thereby becoming Loews Cineplex Entertainment.

Galaxy Entertainment Inc. was established in 1999 by Ellis Jacob, a former chief operating officer of Loews Cineplex Entertainment, and Stephen Brown, a former Cineplex chief financial officer. With investments from Onex Corporation and Famous Players, the new company focused on smaller markets that were usually served by smaller theatres and old equipment, opening large, major chain-style locations under the Galaxy Cinemas banner. By 2003, Galaxy Entertainment had grown to 19 theatres and $75 million in box office revenue.

In 2001, Loews Cineplex Entertainment (a 1998 merger of Universal Pictures' Cineplex Odeon and Sony's Loews Theatres) underwent bankruptcy due to the economic recession of the early 2000s. In June 2001, Onex Corporation announced its intent to acquire Loews Cineplex; as part of the deal, Loews Cineplex would close 46 cinemas (including 25 in Canada), and Onex would acquire the company for $1.3 billion with Oaktree Capital Management as a partner.