The script was written in 2007 as "The Way Back", but the title was later changed to avoid confusion with the film The Way Back (2010). The title refers to the "way back seat," the 1970s colloquial expression for the third, often-hidden seat located in the cargo section of a station wagon.
Sam Rockwell would often improvise and joke around on the loudspeaker during scenes. One time, forgetting that there were children around, he made an inappropriate joke about herpes, which upset the owner of the park. Rockwell had to go and apologize so that they could continue filming.
Even though the Buick Estate Wagon used in the film utilized a 455 hp gasoline powered V8, near the end of the film when Steve Carell's character is fueling up, he is shown pumping diesel fuel into the tank.
In the first scene at the water park, Owen is eating a pop-tart. Throughout the scene, the amount of pop-tart eaten and the direction it is facing in his hand changes several times.