Wolfgang Mommsen was born in Marburg, the son of the historian Wilhelm Mommsen and great-grandson of the Roman historian Theodor Mommsen. He was educated at the University of Marburg, University of Cologne and University of Leeds between 1951 and 1959. He was assistant professor at the University of Cologne (1959–1967), full professor University of Düsseldorf (1967–1996) and served as director of the German Historical Institute in London between 1978 and 1985. In 1965, he married Sabine von Schalburg, with whom he had four children.
Mommsen wrote a biography of Max Weber in 1959. His main areas of expertise were in 19th century-20th century British and German history. His interests were wide-ranging and he wrote about diplomatic, social, intellectual, and economic history. Mommsen championed a Sonderweg ("special path") interpretation of German history. Echoing the views of Hans-Ulrich Wehler and Fritz Fischer, he argued that 19th century Germany was only partially modernized. Economic modernization was not accompanied by political modernization. Much of Mommsen's comparative studies of British and German history concern why, in his view, the British had both a political and economic modernization while the Germans had only the latter. An Anglophile, Mommsen very much enjoyed teaching and living in Britain.
In Mommsen's view, the foreign policy of the Second Reich was driven by domestic concerns as the German elite sought distractions abroad to hold off demands for democracy at home. For Mommsen, the major responsibility for the outbreak of the First World War rests on Germany's shoulders. Furthermore, the November Revolution of 1918 did not go far enough and allowed the pre-1918 elite to continue to dominate German life, thus leading inevitably to the Third Reich. Mommsen has written books condemning appeasement.
In 1998, several younger German historians criticized Mommsen for not denouncing the Nazi past of his mentors while a university student in the 1950s.
- Max Weber und die deutsche Politik, 1890-1920, 1959.
- "The Debate on German War Aims" pages 47–74 from Journal of Contemporary History, Volume 1, 1966.
- "Die latente Krise des Deutschen Reiches, 1909-1914" from Handbuch der deutschen Geschichte, Volume 4: Deutsche Geschichte der neuesten Zeit von Bismarcks Entlassung bis zur Gegenwart, 1973.
- The Age of Bureaucracy: Perspectives on the Political Sociology of Max Weber, 1974.
- "Society and War: Two New Analyses of the First World War," Journal of Modern History Vol. 47, No. 3, September 1975,
- Imperialismustheorien, 1977.
- Der europäische Imperialismus. Aufsätze und Abhandlungen, 1979.
- The Emergence of the Welfare State in Britain and Germany, 1850-1950 co-edited with Wolfgang Mock, 1981.
- Sozialprotest, Gewalt, Terror: Gewaltanwendung durch politische und gesellschaftliche Randgruppen im 19. und 20. Jahrhundert, co-edited with Gerhard Hirschfeld, 1982.
- The Fascist Challenge and the Policy of Appeasement, co-edited with Lothar Kettenacker, 1983.
- The Development of Trade Unionism in Great Britain and Germany, 1880-1914, co-edited with Hans-Gerhard Husung, 1985.
- Imperialism and After: Continuities and Discontinuities co-edited with Jürgen Osterhammel, 1986.
- Bismarck, Europe, and Africa: The Berlin Africa Conference, 1884–1885, and the Onset of Partition, co-edited with Stig Förster and Ronald Robinson, 1988.
- The Political and Social Theory of Max Weber: Collected Essays, 1989.
- “Neither Denial nor Forgetfulness Will Free Us From the Past: Harmonizing Our Understanding of History Endangers Freedom” pages 202-215 from Forever In The Shadow Of Hitler? edited by Ernst Piper, Atlantic Highlands, N.J. : Humanities Press, 1993.
- Intellektuelle im Deutschen Kaiserreich, co-edited with Gangolf Hubinger, 1993.
- Der Autoritäre Nationalstaat, 1990 translated by Richard Deveson into English as Imperial Germany 1867-1918 : politics, culture, and society in an authoritarian state, 1995.
- "Max Weber and the Regeneration of Russia," Journal of Modern History Vol. 69, No. 1, March 1997.
- Mommsen, Wolfgang J. "Neither Denial nor Forgetfulness Will Free Us" pages 202-215 from Forever In The Shadow of Hitler? edited by Ernst Piper, Humanities Press, Atlantic Highlands, 1993 page 209.
- Kallis, Aristotle "Mommsen, Wolfgang J." pages 829-830 from The Encyclopedia of Historians and Historical Writing edited by Kelly Boyd, London: Fitzroy Dearborn Publishing, 1999.