Introduction: This study investigated some contributing factors to stress among mathematics lecturers in higher institutions of learning in Oyo state, Nigeria. Purpose: The study was to find out the contributions of cognitive, intrinsic and systemic factors in causing stress among mathematics lecturers in higher institutions. Methodology: The study adopted a survey research design. The population of the study covered mathematics lecturers in ten (10) selected higher Institutions of learning in Oyo State, Nigeria. Simple random sampling technique was used in the selection of one hundred (100) mathematics lecturers, ten (10) lecturers per institution participated in the study. A self-designed structured questionnaire was used to collect data from the participants in the study. Croabach alpha was used to attain Correlation Coefficient (r = 0.88) which made the instrument reliable for the study. Three hypotheses were tested using the Chi square statistic at 0.05 level of significant. Results: Findings revealed that cognitive factors did affect individual Mathematics lecturer with x2-tab (21.0) < x2-cal (183.31). Also, intrinsic factors do affect the level of stress among Mathematics lecturers with x2-tab (21.0) < x2-cal (86.84), while systemic factors within the school setting did affect stress among Mathematics with x2-tab (21.0) < x2-cal (91..62). Recommendations: Based on findings of the study, it was recommended among others that management of higher institutions of learning should encourage mathematics lecturers to go for break and relaxation every day during break period on the academic time table.