As a kind of ‘criticism from within’, conceptual and critical design inquire into what design is about – how the market operates, what is considered ‘good design’, and how the design and development of technology typically works. Tracing relations of conceptual and critical design to (post-)critical architecture and anti-design, we discuss a series of issues related to the operational and intellectual basis for ‘critical practice’, and how these might open up for a new kind of development of the conceptual and theoretical frameworks of design. Rather than prescribing a practice on the basis of theoretical considerations, these critical practices seem to build an intellectual basis for design on the basis of its own modes of operation, a kind of theoretical development that happens through, and from within, design practice and not by means of external descriptions or analyses of its practices and products.