Ossi may refer to:

• Open Source Seed Initiative, dedicated to maintaining access to plant genetic resources
• Open Source Software Institute, promoter of open-source software solutions in the US Federal, state and municipal government agencies

• Ossi (East Germans), a nickname given to former residents of the country East Germany (GDR)
• Ossian Ossi Blomqvist (1908–1955), Finnish speed skater
• Oskar "Ossi" Bonde (born 1979), the drummer of the rock band Johnossi
• Ossi Kauppi (1929–2000), Finnish ice hockey player
• Ossi Oikarinen (born 1970), Finnish engineer who works in Formula One
• Ossi Oswalda (1899–1948), German silent film actress
• Ossi Reichert (1925–2006), German Alpine skier
• Ossi Runne (1927–2020), Finnish conductor and composer
• Ossi Sandvik (born 1953), Finnish politician

• Order of the Star of Italian Solidarity
• Ossi, Sardinia, a city in the province of Sassari, Sardinia

• Ossie, a given name
• Ozzie, a given name

This disambiguation page lists articles associated with the title Ossi.
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