Mathematics determines whether students' study and work in STEM disciplines such as electrical and electronics. However, there is insufficient data to support this claim. It is also premature to assert that the effect of motivation and instruction factors in mathematics on students' achievement in electricals and electronics is equivocal. Therefore, this study investigated the effects of mathematics achievement, learning motivation, and instructional factors on pre-service teachers' electrical and electronics achievement. Self-administered questionnaires and achievement tests were used to collect data through a cross-sectional design. Although the results showed that instructional factors did not significantly mediate the relationship between mathematics achievement and electrical and electronics achievement, mathematics achievement and instructional factors substantially positively affected electrical and electronic achievement. Furthermore, the results indicated that pre-service teachers who excel in mathematics would likely excel in electrical and electronics because they benefit from instructional practices that activate cognition through direct instruction, facilitation of discourse, challenging tasks, and cognitive autonomy. Consequently, it is recommended that mathematics teacher educators create stimulating and engaging learning environments for their pre-service technical teachers. This will likely improve their performance in electrical and electronics.