Two years after the legalization of same-sex marriages in the Netherlands, 65% of the Dutch population largely or completely disagrees with the statement “gay marriage should be abolished.” This article shows, by way of multinomial logistic regression analysis of survey data, which socializing agents influence one’s attitude toward same-sex marriage after its legalization (FNB2003; N = 2,124). Parents’ attitudes toward homosexuality during one’s youth strongly affect one’s attitude toward same-sex marriage. The strongest determinant is socialization within religious institutions. Religious practice provides an explanation of the differences between members of denominations opposing same-sex marriage. A lower educational level enhances one’s probability of being neutral on abolishing gay marriage. Finally, men and people from non-Western origin are especially likely to oppose same-sex marriage.