Themistocles or Themistoklis may refer to several people:

• Themistocles, Athenian soldier and statesman
  • the Decree of Themistocles, ancient Greek inscription, purported to have been issued under the guidance of Themistocles
• Themistocles Anastasiadis, birth name of Greek journalist Themos Anastasiadis (born 1958)
• Themistokles Cholevas (1926–2007), Greek basketball player
• Themistoklis Diakidis (1882–1944), Greek high jumper
• Themistocles Leftheris (born 1982), American pair skater
• Themistoklis Nikolaidis, birth name of Greek footballer Demis Nikolaidis (born 1973)
• Themistocles M. Rassias (born 1951), Greek mathematician
• Themistokles Rigas (1945-1984), Greek footballer
• Themistoklis Sophoulis (1860–1949), Greek politician
• Saint Themistocles the Martyr of Myra in Lycia, 3rd-century saint
• Sir Themistocles Zammit (1864–1935), Maltese archaeologist, historian, professor of chemistry, medical doctor, researcher and writer

Ships

• SS Themistocles (1907), a ship launched as Moraitis in 1907 and renamed Themistocles in 1908
• SS Themistocles (1911), a ship launched in 1910 and completed in 1911.