This study investigated the integration of English intercultural teaching of Thai secondary school teachers using questionnaires and classroom observations. The results from the questionnaires revealed that participants perceived that they integrated English intercultural teaching at a low level. In the actual classroom, they placed a paramount focus on teaching English intercultural 'knowledge', whereas assessing students' intercultural 'attitudes' and 'behavior' gained the least attention. Finally, it should be noted that the aspects of cultural bias during the teaching practice of participants require further attention.