Dietz is a surname, and may refer to:

• Albrecht Dietz (1926–2012), German entrepreneur and scientist
• August Dietz (1869–1963), a philatelist, editor and publisher
• Bernard Dietz (born 1948), German football player and manager
• Cyrus E. Dietz (1876–1929), Illinois Supreme Court Justice
• Damion Dietz (born 1971), American film writer/director
• Dick Dietz (1941–2005), American baseball player
• Ella Dietz (1847-1920), American actress and author
• Feodor Dietz (1813–1870), German painter
• G. O. Dietz, American football coach and lawyer
• George Dietz, American inventor of Miniature linear vibrotactile actuator
• Hendrik Casimir II of Nassau-Dietz
• Henry Dietz, American professor and author
• Henry G. Dietz, American electrical engineer
• Howard Dietz (1896–1983), American lyric writer and librettist
• Jan Dietz (born 1945), Dutch computer scientist
• Jim Dietz (disambiguation), several people
• Johann Heinrich Wilhelm Dietz [de] (1843–1922), German politician
• Michaela Dietz (born 1982), American actress
• Michael Dietz (born 1971), American actor
• Park Dietz (born 1948), American forensic psychiatrist
• Richard Dietz (born 1977), North Carolina Supreme Court Justice
• Robert H. Dietz (1921–1945), United States Army soldier and a recipient of the Medal of Honor
• Robert S. Dietz (1914–1995), US-American geophysicist and oceanographer
• Sophie Dietz (1820–1887), German operatic soprano
• Steven Dietz, American playwright
• Thomas Dietz (juggler) (born 1982), German professional juggler
• Thomas Dietz (politician) (born 1967), German politician
• William Dietz (disambiguation), several people

Dietz may also refer to:

• R. E. Dietz Company, a lighting and lantern manufacturer

• All pages with titles containing Dietz
• Diez (disambiguation)