Vassilis Angelopoulos (Greek: Βασίλης Αγγελόπουλος; born February 13, 1965) is a Greek American physicist. He is a specialist on space and astrophysical plasmas.

Since July, 2007, he has been on the faculty of the department of earth, planetary, and space sciences and the Institute of Geophysics and Planetary Physics at the University of California, Los Angeles (UCLA). Vassilis is currently the principal investigator of the ELFIN Cubesat mission and co-investigator of ELFIN-L, leading the energetic particle detector (EPD) experiment at UCLA.

He is the principal investigator of THEMIS, a five-satellite and 20-ground-based-observatory mission proposed and managed by the University of California, Berkeley's Space Sciences Laboratory, launched in February 2007. He is also the principal investigator of the ARTEMIS mission, a two-satellite mission around the moon: a collaboration between UCB, JPL and UCLA, proposed in 2008, executed in 2009 and operating since 2010.