CIII-DT (channel 41, cable 3) is a television station in Toronto, Ontario, Canada, serving as the flagship station of the Global Television Network, a division of Corus Entertainment. The station maintains studios at 81 Barber Greene Road (near Leslie Street) in the Don Mills district of Toronto, and its transmitter is located atop the CN Tower in downtown Toronto.

The station reaches much of the population of Ontario through a network of 12 transmitters across primarily the southern and central portions of the province (as a result, it is the de facto Global outlet for the capital city of Ottawa through repeater CIII-DT-6). Since August 29, 2022, CIII-DT serves as the master control hub for all 15 Global owned-and-operated stations across Canada.

Ken Soble, the founder of CHCH-TV in Hamilton, envisioned a national "superstation" of 96 satellite-fed transmitters with CHCH as its flagship. In 1966, he filed the first application with the Board of Broadcast Governors for a network to be branded as NTV—however, the application faced various regulatory hurdles and underwent numerous revisions over the next number of years. The Canadian Radio-television and Telecommunications Commission (CRTC) eventually decided to go ahead with the publicly owned Anik satellite system instead of relying on private communications companies to build Canada's satellite broadcasting infrastructure, placing the NTV application in jeopardy after Power Corporation of Canada, a key investor in the plan, backed out.

In 1970, one of Soble's former employees, Al Bruner, teamed up with Peter Hill to revive the application under new ownership. Bruner and Hill's group, Global Communications, scaled back the original NTV proposal to a network of seven UHF transmitters in Southern Ontario, whose combined footprint would have provided at least secondary broadcast coverage from Montreal to Detroit. Global Communications still aspired to eventually build out Soble's original 97-station network, and viewed the seven-transmitter Ontario chain as an interim step. However, since CHCH was no longer involved in the application, Global's iteration of the plan also required the launch of a new station to serve as its flagship.

The station first signed on the air on January 6, 1974, as CKGN-TV (before its use by the station, the CKGN callsign had previously been used by what is now CTV owned-and-operated station CKNY-TV in North Bay from 1955 to 1962). It branded itself as the "Global Television Network," a name which reflected its then-unprecedented coverage of most of Southern Ontario from six transmitters (a seventh that would have reached Montreal was turned down) fed from a centralized studio. From its launch in 1974 until 2009, the station's main transmitter was licensed to Paris, a small town near Brantford, but Toronto became the station's primary city of licence following an amendment to the channel 41 licence in 2009. Through its entire history, however, the station's main studio facility has been based in a converted factory (built 1954 for Barber Greene Canada Limited) in the Don Mills area of North York (since 1998, located in Toronto).

It had hoped to be distinct from CBC and CTV by airing a number of its own Canadian-made programs. Three months later, however, many of these programs had been cancelled due to deep financial problems. It had made a serious blunder by signing on in the middle of the 1973–74 television season, and prospective advertisers did not have the money to spare for commercial spots. It barely registered as a blip in the ratings; in Toronto, for instance, it only drew a 2.5 share, just a fraction of those drawn by CBC and CTV. Its line of credit was yanked, and it was unable to meet daily expenses.

Amid losses of over a million dollars a month, the network was bailed out by two conglomerates in March 1974 – a Toronto-based group headed by Allan Slaight and a Winnipeg-based group headed by Izzy Asper and Paul Morton. By the fall, Global was forced to scrap its ambitious business model just to survive. Instead, it began airing as much non-Canadian content as allowed (at the time, Canadian content regulations required stations to broadcast domestically produced programs for 60% of its overall schedule, and 50% during prime time), becoming essentially a clone of CTV.

Asper's group bought controlling interest in 1977, making them first western owners of a major Canadian broadcaster. In 1989, Asper and Morton tried to buy out each other's shares, and the Court of Queen's Bench of Manitoba ended the contest by ordering a sale of shares by auction, which allowed Asper and his company, Canwest, to take full ownership.