Transition zone may refer to:
Transition zone (Earth), a part of the Earth’s mantle located between the lower mantle and the upper mantle Transition zone, the region between the near and far fields of a transmitting antenna Transition zone (TZ), a glandular region of the prostatesee Prostate#Zones Zone of transition, a zone in urban planning Ciliary transition zone, a part of the ciliary apparatus.
See also Ecotone, a transition zone between two biomes