The Kansas Turnpike is a 236-mile (380 km) controlled-access toll road that lies entirely within the US state of Kansas. It runs in a general southwest–northeast direction from the Oklahoma border to Kansas City. It passes through several major Kansas cities, including Wichita, Topeka, and Lawrence. The turnpike is owned and maintained by the Kansas Turnpike Authority (KTA), which is headquartered in Wichita.

The Kansas Turnpike was built from 1954 to 1956, predating the Interstate Highway System. While not part of the system's early plans, the turnpike was eventually incorporated into the Interstate System in late 1956 and is designated today as four different Interstate Highway routes: Interstate 35 (I-35), Interstate 335 (I-335), I-470, and I-70. The turnpike also carries a piece of two U.S. Highways: U.S. Highway 24 (US-24) and US-40 in Kansas City.

Because it predates the Interstate Highway System, the road is not engineered to current Interstate Highway standards and notably lacks a regulation-width median. To reduce the risk of head-on collisions, the Kansas Turnpike now has a continuous, permanent Jersey barrier in the median over its entire length. On opening, there was no fixed speed limit on the highway; drivers were merely asked to keep to a "reasonable and proper" limit, although, shortly afterward, signs were erected in certain stretches indicating a maximum speed of 80 mph (130 km/h). From 1970 to 1974 and again since 2011, the turnpike's speed limit has been set at 75 mph (121 km/h); that limit during the earlier period applied only during daytime hours.

Around 120,000 drivers use the turnpike daily. The road features numerous services, including a travel radio station and six service areas. One of these service areas is notable for the presence of a memorial to University of Notre Dame football coach Knute Rockne, who died near the current highway's route.

Since July 1, 2024, the turnpike has utilized open road tolling, with all tolls payable with a K-TAG transponder or via license plate recognition. The turnpike is self-sustaining; it derives its entire revenue from the tolls collected and requires no additional tax money for maintenance or administration.

Early federal plans for a nationwide system of interregional highways did not include a route along or near the present turnpike, instead connecting Oklahoma City and Kansas City via southeastern Kansas and US-69. By the mid-1940s, this route had shifted to roughly the present I-35 alignment, serving Wichita. The only major difference from the present route was between Wichita and Emporia, where the highway ran north to Newton before turning northeast along US-50.

In the early 1950s, toll roads were gaining in popularity as a mechanism for funding new superhighways. This trend started with the Pennsylvania Turnpike in 1940, which was mimicked by other toll roads in New York, New Jersey, several New England states, West Virginia, Ohio, and Colorado. In October 1951, the Highway Council of the Kansas Chamber of Commerce researched the possibility of integrating the state into a potential cross-country turnpike system. Eastern Kansas was also included in an interstate turnpike system stretching from Galveston, Texas, to Saint Louis, Missouri, via Kansas City, that was proposed by Oklahoma Governor Johnston Murray. Many firms from construction industries, as well as those concerned about the state's economic development, worked to have legislation passed to allow the turnpike to be constructed. Governor Ed Arn and Gale Moss, the State Highway Director, were two major proponents of the turnpike concept.

The turnpike idea was an attractive one because initial construction was to be financed by the private sector via sales of revenue bonds, allowing state highway funds to be used for other important projects. The new toll road would also reduce traffic, and thus maintenance costs, on existing roads. There was also a concern that if Kansas lagged behind in turnpike construction, it might be bypassed by toll roads in other states, leaving it at an economic disadvantage. The toll concept also had the benefit of ultimately putting the financial burden on the drivers who actually used the road, instead of using tax revenue that had been collected from residents statewide. There was some opposition to the plan from both government officials and citizens due to concerns that the toll revenue might not cover the repayments to investors, bankrupting the turnpike authority and burdening the state government with the remaining debt. There were also worries about the possibility of the turnpike requiring maintenance before the bonds had been repaid. Some critics also felt that the high speeds typical of turnpike driving were unsafe. As right-of-way for the project was obtained, the turnpike drew additional opposition from farmers and ranchers, who objected to the turnpike bisecting their property, making it difficult to access disjointed parcels of land.