Abstract: Learning to solve problems is one of the primary objectives in teaching and learning mathematics. However, results of the different achievement tests continued to show that problem solving is still one of the least learned skills in mathematics which is attributed to several cognitive and affective factors. This study investigated the direct and indirect effects of the identified cognitive and affective factors on the mathematical problem solving performance (MPSP) of Grade 8 students. The sample consisted of 446 students of whom 196 (44%) were males and 250 (56%) were females. Data were gathered using achievement tests and survey