Primary mathematics teachers' (N = 521) personal goal orientation and instructional practices were examined based on questionnaire responses. The teachers (grades 2 and 3) were oriented towards mastery goals and mastery approaches to instruction, and reported high teaching efficacy. Strong positive relation between performance orientation and performance instructional practices was established, and correspondingly between mastery orientation and mastery instructional practices. Positive relations between students' (N = 9,980) basic mathematics performance (measured by paper and pencil tests) and both teacher mastery orientation and teaching efficacy were also found. Results indicate that mastery oriented teaching strategies are crucial for fostering basic mathematical competencies in primary students.