Grosu or Grossu is a Romanian surname that may refer to:
- Alexandru A. Grosu, Moldovan football midfielder
- Alexandru Sergiu Grosu, Moldovan football striker
- Alina Grosu, Ukrainian child singer
- Anca Grosu (born 1962), Romanian-German radiation oncologist
- Aneta Grosu, Moldovan journalist
- Eduard Grosu, Moldovan footballer
- Gheorghe Grosu, Romanian politician, member of parliament (1990–1994)
- Gurie Grosu, Bessarabian priest and the first Metropolitan of Bessarabia
- Lora Grosu, Moldovan politician, member of parliament (2005–2009)
- Nicolae Grosu, Bessarabian politician, member of parliament (1917–1918)
- Maria Cristina Grosu-Mazilu, Romanian long-distance runner
- Nicole Valéry Grossu, Romanian writer
- Semion Grossu, Moldovan politician
- Sergiu Grossu, Bessarabian-born Romanian writer and theologian