Underage Thinking is the debut album by singer-songwriter Teddy Geiger, released on March 21, 2006.

Geiger wrote or co-wrote all the songs featured on the album herself, as well as a cover of Avion's "Seven Days Without You".

A Japanese edition of the album was released on July 19, 2006, including the two bonus tracks "Do You Even Care" and "Hallelujah".

The special edition includes remixes of Geiger's latest singles, a newly recorded track, and some never-before-heard demos that she made before her mainstream success with Underage Thinking.

The audio portion of the re-release is available on iTunes and Napster along with the exclusive bonus track "Amazingly Fat Cows", one of the first songs Teddy recorded.