Professor Marco B.M. Loos is the director of the Amsterdam Graduate School of Law, which hosts the master's programmes of the Amsterdam Law School. He is professor of Private Law, in particular of European consumer law, at the Amsterdam Centre for Transformative Private Law (ACT) of the University of Amsterdam.

Loos studied Law at the University of Amsterdam (1987-1993) and subsequently wrote his Ph.D. thesis at Utrecht University (1993-1998). From 1997 to 2001 he worked as a lecturer at Tilburg University. Since 2002 he works at the University of Amsterdam, from 2005 on as full professor. In addition, he currently is a member of the Board of Governors of the Stichting Voortgezet Onderwijs Amsterdam-Zuid (a combination of three schools of secondary education in Amsterdam, since 2021; since October 2024 he is the chair of the board), of TWijs (a combination of 34 schools of primary eduction in the Haarlem- region, since September 2025). he is also a member of the Consumer Advice Council of the Dutch Advertising Code Authority (Reclame Code Commissie, since 2024). Previously, he was a member of the Board of Governors of the Dutch consumer organisation Consumentenbond (2015-2023) and of the Stichting toetsing verzekeraars (2022-2026, previously, from 2018-2022, member of the board), and part-time judge at the District Court 's-Hertogenbosch (2002-2014) and at the Court of Appeal 's-Hertogenbosch (2015-2024).   

Loos specialises in European and Dutch contract law and European and Dutch consumer law. He publishes regularly on subjects of European consumer law, including standard contract terms, digital content, consumer sales, and enforcement of consumer law. His list of publications is available at https://www.uva.nl/en/profile/l/o/m.b.m.loos/m.b.m.loos.html.