The Lexus RX is a mid-size luxury crossover SUV sold by Lexus since 1997. The RX series has comprised multiple V6- and hybrid-powered models (such as the RX 300, RX 330, RX 350, RX 400h, and RX 450h), in either all-wheel drive or front-wheel drive versions. Three generations of the Lexus RX have been produced to date. One of the first crossovers, the RX series is designed to combine the functional characteristics of an SUV with ride and features of a luxury-type sedan. The RX has ranked as the one of the best-selling luxury vehicle in the United States.

The Lexus RX first premiered in 1997 as a Lexus concept, followed several months later by debut of the production RX 300 models. In 2003, the second generation RX debuted in the U.S., and the redesigned RX 330 went on sale shortly after. In 2004, the RX line added the world's first luxury-type hybrid, the RX 400h, and the RX 330 was upgraded to the RX 350 for model year 2007. Equivalent versions of the first and second generation models were sold in Japan under the Toyota Harrier nameplate until 2008. The redesigned third generation RX 350/RX 450h models premiered in late 2008.

As one of the first luxury SUVs on the market, the Lexus RX has inspired similar competitors from rival marques. Its commercial success as Lexus' best-selling model has been attributed to the strong reliability reputation of Lexus and the RX line. The RX is also the only Lexus vehicle to be produced outside of Japan, with North American market RX 350s being made at the Cambridge plant in Canada. The RX designation, coincidentally similar to the unrelated Mazda RX-7/RX-8 coupes and the Kia Rio RX-V hatchback in Canada, signifies its place in the Lexus lineup next to the larger GX and LX SUVs.