He's 39.
I remember because of the episode when Homer was moping because he had wasted his life and he's on the bed with Marge and he's like, "I've wasted 38 years of my life" and Marge replied, "You're 39"
posted over a year ago
That's because it was the seventh season when that episode happened.
"Homer's age has increased as the series developed; he was 36 in the early episodes, 38 and 39 in season eight, and 40 in the eighteenth season, although even in those seasons his age is inconsistent." Source: Wikipedia
