Abstract: The study found out, the relationship between Mathematics anxiety and student academic achievement in some selected secondary schools in Southwestern Nigeria. The study adopted the descriptive survey design and simple percentages were used in analyzing the data. Two validated instruments were used in collecting data for the study. The subject of the study was made up of 1750 senior secondary school students selected from 2 secondary schools in each of the Senatorial districts in Southwestern part of Nigeria. The results showed that many of the students were afraid of Mathematics, because of the fear of the subject and the fear of failing tests. The findings also revealed that majority of the students don’t know how to study for Mathematics tests. It was recommended that stakeholders should organize propaganda in the media to educate parents, students and the general public about Mathematics to allay their fear of the subject.