Too often, instructional leadership is perceived as an area of competence for principals with less focus on teachers, especially those with subject leadership responsibilities. In the study reported on here we investigated the perspectives of subject leaders and their perceived competence in instructional leadership as a basis for its correlation. Two hundred and five subject leaders from a purposive sample of 100 primary schools across 5 education districts of the Free State province in South Africa were surveyed on their knowledge, beliefs and perceptions of instructional leadership, in relation to their perceived competence. Data were analysed using descriptive statistics, correlation coefficients and regression. The results show that beliefs about instructional leadership tend to correlate negatively with perceived competencies and make no impact on such competencies. On the other hand, knowledge and perceptions showed significant correlation and are thus considered to be the better predictors of subject leaders' perceived competencies on instructional leadership. Further examination using regression analysis shows that perceptions may have a high impact on perceived competence. Consequently, we recommend interventions to deliberately target subject leaders' perceptions of instructional leadership to promote a more distributed practice of subject leadership in schools.