This paper draws on sociological and philosophical work on educational knowledge and expertise to consider what is distinctive about different traditions of educational inquiry. It is argued that an examination of the character of educational knowledge benefits from scrutiny of the relations between specialised and non-specialised forms of knowledge, and an emphasis on distinguishing forms of educational practice in terms of their underpinning socio-epistemic character. With reference to the work of Durkheim, Bernstein and social realism, it is suggested that traditions of educational inquiry can be differentiated by the extent to which they recognise the distinct value of specialised educational knowledge and by which they offer a conceptualisation of educational practice as a specialised activity for which systematic knowledge is necessary. Various traditions of inquiry are briefly explored in these terms (i.e. foundation disciplines, German educational thought and practice-centred traditions).