This quantitative study investigated the extent and contexts of target language (TL) use in English language classrooms. Participants were 2,906 students from seven secondary schools and four universities in the more developed cities in southern China. They were put into five groups according to their educational stage and whether their content subjects were taught in the TL. A 5-point interval scale was used in the questionnaire to elicit responses about the amount of TL use. The mean percentages of TL use reported by different groups were compared using "t"-test or one-way analysis of variance (ANOVA). How classroom-related factors and institutional factors associated with the amount of TL use in the English-as-a-foreign-language (EFL) classrooms were analysed. Findings include: (1) the amount of TL use dropped significantly from the junior secondary level to the senior secondary level, during which more concerns were given to prepare students for the university entrance exam; (2) a significantly smaller amount of TL use was reported in less well-resourced secondary schools; and (3) a significantly larger amount of TL use was reported in the secondary schools and universities if the TL was also used as the medium of instruction for content subjects. Findings have implications for language teaching policy and practice.