Article HistoryThis study aimed to determine the association between sleep quality (SQ) and physical fitness components among 13-14 years old male students in a secondary school in Kota Kemuning Selangor, Malaysia. The sample consist of 162 students purposively selected according to their physical fitness levels (SEGAK test score). They were in three categories; higher (A score: 4.33±0.21, N=54), intermediate (B score: 3.27±0.26, N=54) and lower (C score: 2.35±0.36, N=54). The SEGAK tests were consist of BMI, step test, push-up, curl-up, and sit and reach. Pittsburgh Sleep Quality Index (PSQI) selfreported questionnaire was used to measure SQ. The descriptive analysis and Pearson Product Moment test were used to analyze the data. The results showed 51.8% of the students with higher fitness level, and 42.6% of the intermediate level reported "very good" SQ while only 25.9% of the lower fitness level had "very good" SQ. The correlation between overall SQ score and total fitness score was (r=-.282; p <0.001). The physical fitness components which significantly associated with SQ were BMI (r=.211; p=0.007), cardiovascular fitness (r=.319; p <0.001), endurance and strength of abdominal muscles (r=-.197; p =.012), and lower back muscles flexibility (r=.315; p <0.001). These findings illustrated no significant association between SQ and "endurance and strength of shoulder muscles" (r=-.142; p =0.072). The findings suggest that, cardiovascular fitness level and lower back muscles flexibility can improve overall SQ, similarly normal BMI, and endurance and strength of abdominal muscles among secondary school children. Physical educators should be encouraging students to improve their physical fitness components for higher fitness level to enhance their SQ as an important part of healthy life. Contribution/ Originality:This study is one of very few studies which investigated association between sleep quality (SQ) and physical fitness components. SQ is essential for health and wellbeing. Many school children cannot achieve excellence in academic and sports because of weak physical condition due to poor SQ. It showed which physical fitness component can significantly improve SQ among school children.