This study examines the impact of teacher expectations on gender differences in attitudes toward learning mathematics among secondary school students in Keiyo District, Kenya (2001–2004). Research has consistently shown that gender disparities in mathematics performance and participation are influenced by social factors, including teacher expectations. Using a descriptive survey design and ex-post facto approach, the study involved 300 students (150 boys and 150 girls) and 15 mathematics teachers (5 female and 10 male) from selected secondary schools in Keiyo District. Data was collected using questionnaires and face-to-face interviews and analyzed through descriptive and inferential statistics, including Chi-square tests.The findings indicate a significant relationship between students' perceptions of teacher expectations and their attitudes toward mathematics. Boys were more likely to perceive positive reinforcement from teachers, while girls often felt overlooked or assumed to struggle with the subject. Additionally, teachers had higher expectations for boys, which influenced classroom interactions, engagement, and student motivation. The study also found that teacher willingness to assist students had a stronger impact on boys' attitudes than on girls' attitudes. These findings highlight the need for gender-sensitive teaching strategies and equitable classroom practices to ensure that both boys and girls develop positive attitudes and confidence in mathematics.