Studies are reviewed showing that the social status of a high school has a small independent effect on the college intentions of its students, over and above the effects of their family status and mental ability. This finding is analyzed with data from the Educational Testing Service's 1955 sample of 35,330 students in 518 American high schools. College intentions of students were found to be an effect of the social class composition of the school rather than of formal features of the school organization. The positive effects of school status on college intentions are found to mask a negative effect--in schools with students of high average ability, students of any given ability and status are less likely to have college intentions, presumably because internal standards of competition rise. When this hidden negative effect is held constant, the positive effect of school status on college intention increases. The conditions and mechanisms of the negative effect are considered. (Author/MF)