Precursor or Precursors may refer to:

• Precursor (religion), a forerunner, predecessor
  • The Precursor, John the Baptist

• Precursor (bird), a hypothesized genus of fossil birds that was composed of fossilized parts of unrelated animals
• Precursor (chemistry), a compound that participates in the chemical reaction that produces another compound
• Precursor (physics), a phenomenon of wave propagation in dispersive media
• Precursor in the course of a disease, a state preceding a particular stage in that course
• Precursor cell (biology), a unipotent stem cell
• Earthquake precursor, a diagnostic phenomenon that can occur before an earthquake
• Gehrlein Precursor, a glider
• LNWR Precursor Class (disambiguation), classes of passenger locomotives developed for the London and North Western Railway

• Precursor race, a hypothetical alien civilization that inhabitated the Earth before the early human civilizations
• Precursors in the Halo series, an extremely advanced race that preceded and were destroyed by The Forerunners
• Precursor, a 1999 novel set in C. J. Cherryh's Foreigner universe
• Precursors, a fictional race (now extinct) of ancient beings in the board game Cosmic Encounter
• Precursors, a fictional alien race in the Star Control video game series
• Precursors, a fictional race of ancient beings in the Jak and Daxter video game series
• Precursors, a fictional alien race in the video game Galactic Civilizations II: Dread Lords
• Precursors, a fictional, almost extinct alien race that supposedly created humanity in the Assassin's Creed video game series
• Precursors, a fictional, evil alien race that created the Kaiju in the movie Pacific Rim and its sequel Pacific Rim: Uprising
• Precursors, a fictional and extremely advanced alien race in the video game Subnautica.

• Precursors of film
• The Precursors (video game), a video game from Kyiv-based developer Deep Shadows