Vassallo or Vasallo is a surname of Italian and Spanish origin. It is a common surname in Malta. Notable people with the surname include:

• Andrea Vassallo (architect)
• Andrea Vassallo (footballer) (born 1997), Italian footballer
• Ángel Daniel Vassallo (born 1986), Puerto Rican basketball player
• Angelo Vassallo (1953–2010), Italian politician
• Antonio Maria Vassallo (c. 1620–1664/1673), Italian Baroque painter
• Barrie Vassallo (born 1956), Welsh footballer
• Francisco Vassallo (1789–1849), Puerto Rican mayor
• Ġan Anton Vassallo (1817–1868) Maltese writer, poet and academic
• Gustavo Vassallo (born 1978), Peruvian footballer
• Gustavo Vassallo (fencer) (1920–2012), Argentine fencer
• Harry Vassallo, Maltese politician
• Italo Vassallo (1940–2021), Italian-Eritrean footballer
• Jesse Vassallo (born 1961), Puerto Rican swimmer
• Joseph Vassallo (born 1964), American actor
• Luciano Vassallo (1935–2022), former footballer of Eritrean and Italian origin
• Martín Vassallo Argüello (born 1980), Argentine tennis player
• Nicla Vassallo (born 1963), Italian philosopher and writer
• Salvador Vassallo (businessman) (1942–2007), Puerto Rican businessman
• Salvador Vassallo (swimmer) (born 1968), Puerto Rican swimmer
• Víctor Vassallo (born 1960), Puerto Rican businessman, athlete, and politician
• Industrias Vassallo, Puerto Rican manufacturing company