GRT began its operation on January 1, 2000 by assuming the operations of the former Kitchener Transit (which also served Waterloo) and Cambridge Transit from the cities, and placing them under the jurisdiction of the regional government. By the end of that year, operations had been fully synchronized and services established to connect the two operating areas, which was not previously possible by public means.

In recent years, many low-floor, wheelchair-accessible buses have been purchased, and these now constitiute the majority of the fleet. Most operating buses are less than 20 years old; a few older buses are used primarily for high-school special runs.