Our objectives were to assess quality parameters and chemical composition, and to evaluate the effects of sex, muscle and aging time on the quality of meats from Wagyu × Angus cross cattle reared under tropical conditions. Analyses were performed on the longissimus thoracis, semitendinosus and triceps brachii muscles obtained from chilled carcasses of a total of 30, 24-month-old, male (immunocastrated) and female animals (15 each sex). An effect of sex (P ≤ 0.05) was observed for subcutaneous fat thickness, marbling score, and ribeye area. The longissimus thoracis muscle from males was less (P < 0.0001) marbled than that from females, but males had greater subcutaneous fat thickness (P = 0.0001) and greater ribeye area (P = 0.0411) compared with females. No effect of sex (P ≥ 0.05) was observed for fat colour measures. An interaction effect of sex and muscle (P < 0.03) was detected for cooking loss, yellow intensity (b*), ash, and fat. Main effect of sex was not observed (P > 0.07) only for the ultimate pH and water-holding capacity. Greater shear force and moisture values were observed (P < 0.01) in meat from males than that from females, but a greater value of luminance (L*), red intensity (a*), chroma (C), hue (Ho), dry matter and protein was observed (P < 0.001) in meat from females than that from males. Main effect of muscle was not observed only for water-holding capacity (P = 0.13). Ultimate pH and shear force values were lesser (P < 0.001) in the longissimus thoracis muscle compared with other muscles. The triceps brachii muscle had the least (P ≤ 0.001) L* and Ho values among muscles, whereas the semitendinosus muscle had the greatest values of a* and C (P < 0.001). The semitendinosus muscle presented the greatest (P < 0.01) protein content compared with other muscles, although not differing in moisture and dry matter content from the triceps brachii muscle. An interaction effect of sex × aging time was observed for ultimate pH (P = 0.0110), meat colour parameters (except for Ho; P ≤ 0.01), and fat L* (P = 0.0025). Greater cooking loss, shear force, and fat a* values were observed (P < 0.01) in meat from males than that from females, but greater values of meat Ho, fat a* and Ho, dry matter, and protein were observed (P ≤ 0.03) in meat from females than that from males. Meat aging of longissimus thoracis reduced shear force. Based on these findings, we recommend that meat from Wagyu × Angus cross cattle should be aged during 7 days because, although differences between 7 and 14 days were observed in either aging times, meat subjected to this process is considered as very tender, based on shear force values. In addition, aging in a shorter period of time can reflect on costs by reducing particularly those related with energy, due to less refrigeration time.