This article examines Lacan's psychoanalytically derived social theory as to its appropriateness for understanding aspects of planning practice. Lacan theorized not only about language and culture, but also about that which resides outside of symbolization and underlies human desire, to provide an understanding of human subjectivity, identity and motivation. We discuss how a Lacanian critical social theoretical approach could be pertinent to analysis of the complex mixture of hybrid processes ¿ technical, collaborative and political ¿ that comprise planning development assessment. We outline key Lacanian concepts including the mirror-stage, jouissance, the Four Discourses and the `big Other' and their applicability to understanding development assessment and regulation.