Imperfectum (Latin "unfinished" or "incomplete") may mean:

  • Imperfect, a verb form
  • Opus Imperfectum, an early Christian commentary on the Gospel of Matthew
  • in the Middle Age theory of music for tempi - tempus imperfectum and tempus imperfectum diminutum - see Mensural notation for consonances see Consonance and dissonance#Antiquity and the middle ages