A discussion of schema theory as it relates to the learning of English as a Second Language reviews related research and its implications for classroom instruction. The first section looks at schema theory in general and content schemata in particular, focusing on how they affect reading comprehension. Studies of non-native speakers, schema theory, and reading are reviewed, and some English classroom applications of what is known about schemata are recommended. A study using intermediate and advanced non-native speakers of English from East Asia is reported. The results of this study indicated that second-language readers, particularly those with intermediate reading proficiency, make use of prior knowledge in reading to compensate for inadequacies in proficiency and depend on content vocabulary in combination with prior knowledge to achieve comprehension. The discussion concludes with implications for the second-language classroom and recommendations for future research. It is recommended that teachers be aware of the prior knowledge required for the reading passages used in the classroom, and that additional classroom research addressing this issue be undertaken. (MSE)