This study aims to develop students' knowledge of tolerance through learning the history of the Indonesian national movement in multicultural classes. The research questions are: (1) what kinds of tolerance knowledge are perceived as tolerance or intolerance deeds by undergraduate history students at Universitas Negeri Semarang? (2) How are tolerance behaviors performed as tolerance or intolerance deeds by the undergraduate history students? and (3) What factors are perceived to contribute tolerance or intolerance deed by the undergraduate history students? This research was conducted using an ethnographic design with Grounded Theory. The research involved 25 students of the History Education Undergraduate Program at Universitas Negeri Semarang as participants. Data were collected through in-depth interviews and observation. The correctness of the data was checked using triangulation and member check techniques. The results of the study are: (1) tolerance is defined as knowledge that is rooted in the history of the Indonesian national movement, and the basis for the establishment of the independence of Indonesia, however, intolerance is a historical idea, emerging as the egoism of certain groups in the form of sentiment and violence; (2) an attitude of tolerance is not only respecting diversity but also caring for and maintaining it to become knowledge that must belong to every individual. Intolerance is an attitude that leads to disintegration and conflict, its activities are coercive and followed by violence; and (3) factors that contribute to the development of tolerance are Pancasila ideology, multiculturalism, and historical knowledge. Hence, this study concludes that tolerance is seen as an idea that views humans from any ethnic, cultural, and religious background as having equality seen from the perspective of nationality and humanity.