This volume constitutes the proceedings of the sixth European Conference on Object-Oriented Programming (ECOOP), held in Utrecht, The Netherlands, June 29 - July 3, 1992. Since the "French initiative" to organize the first conference in Paris, ECOOP has been a very successful forum for discussing the state of the art of object orientation. ECOOP has been able to attract papers of a high scientific quality as well as high quality experience papers describing the pros and cons of using object orientation in practice. This duality between theory and practice within object orientation makes a good example of experimental computer science. The volume contains 24 papers, including two invited papers and 22 papers selected by the programme committee from 124 submissions. Each submitted paper was reviewed by 3-4 people, and the selection of papers was based only on the quality of the papers themselves.