Innovations in the world of work are not a clearly defined subject in innovation research. The chapter first delimits the phenomenon as organizational innovations and points out differences to technical and institutional, and similarities to social innovations. A central feature of this type of innovation lies in their embeddedness in organizational rationalization processes. Thus, analysis focuses in a sociology of work perspective on rationalization processes and on corresponding changes in the quality of work and work organization. The characteristics of innovations in the world of work are then determined more precisely by reference to exemplary workplace innovations (Taylor’s principles of scientific management, Toyotism, systemic rationalization, post-Taylorist, forms of work organization, trust-based working time, and Internet-based open innovation). It becomes clear that innovations in the world of work take place in organizations, i.e., in a decentralized, asynchronous, and heterogeneous way. Finally, the initial (tentative) classification of innovations in the world of work as a subtype of social innovations is questioned on several counts, and the significance of the contribution is reflected upon.