The present study reveals that there is a gender bias in estimates of spouses' political expertise. Data were collected from married couples in one city in north-eastern Japan and the results showed that when all respondents were included, the estimation of spouses' political expertise was moderately accurate. However, while husbands' estimates of the political expertise of their wives were lowered and less accurate, wives' estimates of the political expertise of their husbands were more accurate. The implication of these findings for the political equality of males and females is discussed.