The importance of mathematics to the effective daily living and contributions to the scientific and technological advancement of the society cannot be over-emphasized. As important as this subject is, there seems to be a lot variable that promote or inhibit the pupils' performance in it as various level of Nigerian educational system. The study investigated mathemaphobia and teaching-learning materials as correlates of pupils' achievement in mathematics. Correlation design was adopted in the study. A sample size of 1,080 students and 48 mathematics teachers were randomly selected for the study. Three instruments (Students Mathemaphobia Questionnaires (SMQ), Teaching-learning Materials Inventory (TMI) and Mathematics Achievement Test) were used for data collection. SMQ was adapted from Sokun (1998) and was revalidated by the researcher while SMQ and TMI were constructed and validated by the researcher. The results of the finding showed a linear relationship between the predictors and the criterion; the combination of predictor variables and students achievement in basic mathematics yielded a multiple correlation of 0.574 with students' achievement in basic mathematics. The multiple correlation of 0.574 indicates that there is moderate relationship between the predictors and the students' achievement in basic mathematics; it implied that the obtained regression equation resulting from the set of the four (4) predictor variables allow reliable prediction of students' achievement in Mathematics. The four predictor variables accounted for 30.7% of the observed variance in the students' achievement in basic mathematics; only mathemaphobia contributed significantly to the prediction model while the remaining predictors' contributions were not significant. The study recommends adequate provisions of teaching materials to various basic schools on Oyo state among others.