Diego Mario Francisco Osella (born 19 July 1970 in Acebal, Santa Fe), is a former Argentine footballer and manager who played as a defender for clubs of Argentina and Mexico and managed in clubs of Argentina and Chile.

• Newell's Old Boys 1993–1994
• San Luis Potosí 1994–1995
• Almirante Brown de Arrecifes 1996–1997
• Central Córdoba 1997–1998
• Almirante Brown de Arrecifes 1998–2001
• Tiro Federal 2001–2004

• La Emilia 2006
• Sportivo Las Parejas 2006
• La Emilia 2006–2008
• San Luis de Quillota 2009–2010
• Tiro Federal 2010
• Everton 2010–2011
• Patronato de Paraná 2013
• Colón de Santa Fe 2014
• Club Olimpo 2015–2016
• Newell's Old Boys 2016–2017
• Belgrano 2018–2019
• FBC Melgar 2019

• San Luis de Quillota 2009 (Torneo Clausura Chilean Primera B Championship)

• Diego Mario Francisco Osella at BDFA (in Spanish)
• D. Osella (Diego Mario Osella) coach profile at Soccerway