This study investigated the relationship between teacher leadership and professional competency on student academic accomplishment in vocational colleges in Oman. A questionnaire was instructed and conducted from post foundation students across the seventh vocational colleges in the Sultanate of Oman to collect data. A quantitative research approach was adopted to analyze the data. Built on Kane's comprehensive framework of teacher leadership (2009); Fenollar, Roman and Cuestas' integrative model of the antecedents of academic performance (2007), the present study formulated a new framework to fit into the Omani context education. SPSS was used to analyze data. The study showed that all the main hypotheses of the study are accepted. The study concluded that there is a positive relationship between teacher leadership, professional competency and student academic performance in the English language. Such a positive relationship lies in that students are highly affected by their teachers' leadership skills and professional competencies. Future research is needed to investigate the relationship between teacher gender, age, experience, and qualification as independent variables and student academic performance at vocational colleges in the Sultanate of Oman.