This chapter explores the development of ‘social science’ and ‘sociology’ in Japanese academic discourse. ‘Sociology’ was initially established as a distinct discipline, thanks to pioneers like Toyama and Takebe at Tokyo Imperial University. At the same time, ‘social science’ emerged as a broader framework comprising various disciplines. Initially, sociology in Japan developed its own unique character, blending Western sociological theories (particularly those of Comte and Spencer) with Eastern philosophical traditions, especially Confucianism, as exemplified in Takebe’s General Sociology. Instead of being viewed as merely a branch of social science or a collection of various social sciences, sociology in Japan established itself as an independent field with its own theoretical foundations and methodological approaches while maintaining dialogue with other social sciences. Within synthetic sociology, it acted as a dominant concept encompassing social sciences. Notably, efforts were made by sociologists to establish ‘social science’ as a collective term for various disciplines, while it was also referenced in anarchist discussions. Despite being infrequently used as an overarching term, it was employed by Japanese sociologists and social activists, connecting it to the early notion of ‘sociology’ as a unifying concept. Eventually, ‘sociology’ was recognized as the leading concept for social sciences in Japan, while ‘social science,’ particularly in connection with Marxism, gained prominence through the initiatives of the Social Science Society at Tokyo Imperial University.