Seven hundred years into the future, the Earth has become overrun with garbage and waste as a result of consumerism. The surviving humans abandon Earth on a massive spaceship called the Axiom while robots called WALL-Es, invented by Professor Simon, dispose of the waste. However, the majority of the WALL-Es eventually dysfunction, leaving only one WALL-E left. WALL-E spends his time compacting debris and building with them. He also lives in a garage with his friend, a cockroach. WALL-E becomes lonely, being the only survivor of the cleaning robots. At some point, he discovers a small plant and takes it to his garage. Soon afterwards, a spaceship lands on Earth and deposits a robot named EVE, who WALL-E becomes infatuated with. However, EVE continuously ignores WALL-E in favor of searching for vegetation.
WALL-E eventually manages to take EVE to his garage, where he attempts to entertain her. He eventually shows her the plant, which causes EVE to store it in her containment capsule and send off a signal to the spacechip before going into hibernation mode. A confused WALL-E continues spending time with her despite her lack of response. Days later, the spaceship returns and reclaims EVE. Horrified, WALL-E hitches a ride on the ship, which flies to the Axiom, where WALL-E and EVE are examined. EVE is taken to the ship's commander while WALL-E encounters several humans and robots on the ship, including a scurrbing robot named M-O. The humans on the Axiom have become obese and thus unable to move, and are catered around as a means of transportation.
AUTO, the ship's auto pilot system, contacts Captain McCrea to arrive on the bridge. McCrea becomes ecstatic at the prospect of recolonizing Earth and reactivates EVE, but finds the plant to be missing. WALL-E and EVE are taken to the repair bay, where WALL-ME mistakes EVE to be getting harmed and obliterates the repair bay in an attempt to save her. Security robots take pictures of the two and WALL-E and EVE are labelled as renegade robots. EVE attempts to jettison WALL-E back to Earth, but WALL-E discovers the plant being placed in the pod by AUTO's assistant, GO-4. WALL-E and the plant are jettisoned into space in the escape pod, but WALL-E exits the pod with an escape hatch and the fire extinguisher. WALL-E and EVE then re-enter the Axiom through the garbage chute.
AUTO reveals he was the one who stole the plant, following a directive issued centuries ago when Earth was considered uninhabitable. AUTO tasers WALL-E and knocks him and EVE into the garbage chute, along with the plant. M-O manages to rescue WALL-E and EVE before they are knocked into space, but WALL-E is severely damaged. EVE realizes the repairs for WALL-E are stored in his garage at Earth and attempts to take the plant to the holo-detector to activate the ship's hyperjump. McCrea opens the holo-detector and fights AUTO and GO-4 on the bridge. GO-4 is destroyed, but AUTO partially crushes WALL-E by slamming the holo-detector on him. McCrea eventually manages to deactivate AUTO while EVE places the plant in the holo-detector, freeing WALL-E and sending the ship on a hyperjump to Earth.
Upon reaching Earth, Eve takes a damaged WALL-E to the garage, where she repairs and reactivates him. However, WALL-E reverts to his original programming as a cleaning robot and doesn't recognize EVE. A heartbroken EVE kisses WALL-E, which jolts his memory and restores his personality. The two reunite with McCrea and the other humans, who begin to restore Earth's environment, along with the robots.
- Ben Burtt as WALL-E, a centuries-old cleaning robot with developed sentience.
- Elissa Knight as EVE, a robot probe.
- Jeff Garlin as Captain B. McCrea, the space captain of the Axiom.
- Fred Willard as Shelby Forthright, CEO of the Buy n Large Corporation.
- MacInTalk as AUTO, the autopilot artificial intelligence.
- John Ratzenberger as John, a human living on the Axiom.
- Kathy Najimy as Mary, a human living on the Axiom.
- Sigourney Weaver as Ship's Computer, the voice of the Axiom's computer.