This paper estimates the effects of family-background characteristics on student performance in the US and 17 Western European school systems. Family background has strong effects both in Europe and the United States, remarkably similar in size. France and Flemish Belgium achieve the most equitable performance for students from different family backgrounds, and Britain and Germany the least. Equality of opportunities is unrelated to countries? mean performance. Quantile regressions show little variation in family-background effects across the ability distribution in most countries.