Females' underperformance in mathematics is discussed as a function of negative expectancies by parents, teachers, and peers. These negative expectancies of significant others lead to negative self-expectancies and negative attitudes about mathematics on the part of female students. These negative expectancies and attitudes lead to lower performance, reinforcing parents' and teachers' negative expectancies. Thus a cycle of low expectancies leading to low performance leading to even lower expectancies is perpetuated. Some reasons this cycle persists are: (1) girls, more than boys, tend to believe that mathematical ability is something individuals either have or do not have; (2) girls are more math anxious than boys; (3) girls may believe that "girls just cannot do math"; (4) girls' belief that their ability is so low that no amount of work will compensate, may drain their willingness to persist; and (5) girls may self-handicap by withholding effort. Implications of this continuing cycle and possible ways to break it are discussed. Contains 10 references. (Author/SW)