Laurens, Iowa, 1994. Alvin Straight (Richard Farnsworth) is a 73-year-old frail old man who walks using sticks, and lives with his slow-witted daughter Rose (Sissy Spacek). One night, during a raging thunderstorm, Alvin gets a phone call from a hospital informing him that his 75-year-old estranged brother Lyle (Harry Dean Stanton) has suffered a stroke.

Determined to meet and patch things up with his brother before either one of the dies, Alvin decides to visit him. The trouble is that Lyle lives over 300 miles away in Mount Zion, Wisconsin, and Alvin is legally unable to drive a car due to his bad health and poor eyesight. To make matters worse, Rose cannot drive either and they have no money for a bus fair. Undaunted, Alvin hatches a plan: he will drive his Rhoda lawn mower all the way.