Tetrode can refer to:

• Tetrode, an electronic device with four active electrodes, such as a vacuum tube
  • Beam tetrode
  • Field-effect tetrode, a solid-state device
• Tetrode (biology), an electrode used in biology to sample neural signals
• Tetrode transistor, a transistor with four active terminals
• Sackur–Tetrode equation, an expression for the entropy of a monatomic classical ideal gas
• Hugo Tetrode, a Dutch physicist (1895–1931)
• Willem Danielsz van Tetrode, a Dutch sculptor (ca. 1530 – ca. 1587)