| Oldham, Lindsay Joanna | The evolution of dark and luminous structure in massive early-type galaxies | 2017 | University of Cambridge | GMOS-N/NIFS+LGS | UK |
| Oio, Gabriel
| Propiedades espectroscopicas de galaxias Narrow Line Seyfert 1 | 2018 | Universidad Nacional de Cordoba | GMOS-N | Argentina |
| Nysewander, Melissa C. | Exploring optically dark and dim gamma-ray bursts: instrumentation, observation and analysis | 2006 | The University of North Carolina at Chapel Hill | GMOS-S | USA |
| Noyola, Eva | Central dynamics of globular clusters | 2007 | University of Texas at Austin | GMOS-S | USA |
| Norris, Mark Anderson | The formation of early-type galaxies | 2008 | University of Durham | GMOS-N/GMOS-S | UK |
| Noble, Allison | Dusty star-forming lalaxies within high-redshift galaxy clusters | 2014 | McGill University | GMOS-N | Canada |
| Nilo-Castellon, Jose Luis | C´umulos de galaxias de baja luminosidad en rayos-X | 2013 | Universidad Nacional de Cordoba | GMOS-N/GMOS-S/NIRI | Argentina |
| Nielsen, Eric Ludwig | On the road to imaging extrasolar planets: | 2011 | The University of Arizona | NIRI+ALTAIR/NICI | USA |
| Navarete, Felipe Donizeti Teston | The Formation of High-Mass Stars: from High-Mass Clumps to Accretion Discs and Molecular Outflows | 2018 | University of Sao Paulo | NIFS+ALTAIR | Brazil |
| Naud, Marie-Eve | Detection and characterization of distant giant exoplanets around low-mass young stars using direct imaging | 2016 | Universite de Montreal | GNIRS/GMOS-S/NICI/PHOENIX | Canada |
| Morley, Caroline V. | Clouds and hazes in exoplanets and brown dwarfs | 2016 | University of California Santa Cruz | NIRI | USA |
| Morgan, Adam Nolan | Classification, follow-up, and analysis of Gamma-ray bursts and their early-time near-infrared/optical afterglows | 2014 | University of California, Berkeley | GMOS-N/GMOS-S/NIRI | USA |
| Moran, Paul | Multi-wavelength and Polarisation Studies of Pulsars: the Crab, Vela, and PSR J0205+6449 | 2014 | National University of Ireland, Galway | GMOS-N | Other |
| Mooley, Kunal P. | Exploring the dynamic radio sky: the search for slow transients with the VLA | 2015 | California Institute of Technology | GMOS-N | USA |
| Molina Lera, José Alejo | Agrupaciones estelares y la estructura del segundo cuadrante Galáctico | 2020 | Universidad Nacional de La Plata | GNIRS/GMOS-S | Argentina |
| Moerchen, Margaret Marie | Location and origin of dust in circumstellar debris disks: a mid-infrared imaging study | 2008 | University of Florida | TRECS/MICHELLE | USA |
| Modjaz, Maryam | Varied deaths of massive stars: Properties of nearby type IIb, Ib and Ic supernovae | 2007 | Harvard University | GMOS-N/NIRI | USA |
| Miszalski, Brent | New galactic planetary nebulae and the role of central star binarity | 2009 | Macquarie University | GMOS-S | Australia |
| Millar-Blanchaer, Maxwell A. | Planetary systems in polarized light: Debris disk observations and instrumentation | 2016 | University of Toronto | GPI | Canada |
| Meyer, R Elliot | Variation in the Initial Mass Function of Nearby Galaxies: Instrumentation and Observations | 2019 | University of Toronto | NIFS | Canada |
