The study explored the sources of mathematics test anxiety that affect students' performance, the level of mathematics test anxiety among senior high school students, the effect of test anxiety on students' academic performance in mathematics, and gender differences relating to test anxiety among students. The researchers used a descriptive survey design with a quantitative methodology. Multi-stage sampling technique (stratified and simple random) was used to select a sample size of 66 students from public senior high schools in the Cape Coast Metropolis. Data was collected using the test anxiety scale, a self-developed mathematics achievement test and a questionnaire. Data were analysed using both descriptive and inferential statistics. The study found that factors such as misunderstandings of mathematical concepts, fear of failure and embarrassment, exam preparedness, quality of mathematics instruction, and others significantly contribute to students' anxiety while taking mathematics assessments. The results showed a significant negative correlation between anxiety levels and academic performance. Female students were found to have higher levels of test anxiety compared to male students. Teachers should prioritise improving students' comprehension of mathematical concepts and create a nurturing learning atmosphere that promotes experimentation and minimises the fear of making mistakes.