Background: Africa societies place so much emphasizes on fertility so much that couples with infertility after sometime faces considerable emotional, physical and psychological problems. Aim: To explore knowledge of effect of age, obesity, smoking, timing of intercourse, previous STIs and environmental pollutants on fertility among University students. Methods: This was a cross- sectional descriptive study of 420 consented students of Ladoke Akintola University of Technology (LAUTECH), Ogbomoso. They were interviewed through self–administered pre-tested structured questionnaire. Data were entered, analyzed for descriptive and inferential statistics using SPSS 20 statistical package. Results: The mean ± SD age of the respondents was 22 ± 3.16years (range 15–40years). Most (90%) of the respondents were single at the time of interview. A (third 33.3%) participants overestimated by 10years, the age at which fertility starts to decline in women. Only one in four participants correctly identified that female fertility start to decline before 35years. Every one in five participants believed that fertility never declined in men. Only 10% of participants correctly identified the most fertile period in women’s menstrual cycle. Majority of male (60.8%) and female (70.1%) respondents believed that smoking has “a lot,” of effects on male and female fertility respectively. Smoking was believed to have no effect on fertility by females compared with the males (31% vs. 15% P< 0.001).Higher proportion of males than females agreed that alcohol has no effect on fertility (10.3% vs. 3.8% P< 0.001). Obesity was believed to affect fertility by 61.5% and 56.5% of males and females respectively. STIs was said to have “no effect at all” on fertility by 18.5% of participants. With use of modern contraception, 64.5% the participants believed that it has “a lot,” of effect on female fertility, while more male than female said it has “no effect” on female fertility (13.5% vs. 3.3% P< 0.001). Conclusions: Significant gaps exist in the knowledge of the students and modifiable factors that influence fertility. Students with prior information on reproductive health matters demonstrated better knowledge of impact of the modifiable factors on fertility potential of both men and women.