This study investigates the factors associated with the knowledge of contraception among secondary school students in Port Harcourt Metropolis, Nigeria. A descriptive survey research design was employed, involving 900 students from both public and private secondary schools. A validated self-structured instrument with a reliability index of 0.76 was used for data collection. The study found that 76.1% of the respondents exhibited good knowledge of contraception, with 23.9% demonstrating poor knowledge. Disastrously, 80.3% of the students opinioned that contraceptives help prevent sexually transmitted diseases, and 63.7% understood their role in preventing unwanted pregnancies. However, misconceptions persisted, with 16.7% believing that other contraceptives prevent only pregnancy and 59.3% thinking that daily oral pills must be taken daily for effectiveness. Chi-square analysis revealed significant associations between knowledge of contraception and various factors. Age was found to be significant (χ² = 13.633, p = 0.008), with students aged 15-16 years exhibiting better knowledge. Gender was also significant (χ² = 5.705, p = 0.033), as female students had a higher level of understanding. Religion (χ² = 23.564, p = 0.002) and guardian (χ² = 20.432, p = 0.001) both significantly influenced knowledge, with Christian students and those guided by parents demonstrating better knowledge. Based on the findings, it was recommended that government in collaboration with health promotion experts, health educators and school administrators should design, develop and implement a targeted educational interventions to address misconceptions and disparities in knowledge; comprehensive sexual education programs should be implemented, tailored to students diverse backgrounds, and designed to promote gender equity.