Self-Determination Theory: about the quality of work motivation Self-Determination Theory: about the quality of work motivation A. van den Broeck, H. de Witte, M. Vansteenkiste, W. Lens & M. Andriessen, Gedrag & Organisatie, volume 22, November 2009, nr. 4, pp. 316-335. The call for a positive psychology has stimulated research on optimal functioning both in general and in the context of work. The Self-Determination Theory (SDT) might provide a useful framework in which positive work and organisational psychology can be grounded and might stimulate theoretical developments in this field. Starting from a positive concept of man, ZDT reflects upon different aspects of motivation. In the current paper, we describe ZDT and touch upon its relationships with other, and perhaps more well-known, work and organisational theories. We furthermore discuss the empirical evidence in favour of ZDT and illustrate its practical relevance in the context of work.