Maturity or immaturity may refer to:

• Adulthood or age of majority
• Maturity model
  • Capability Maturity Model, in software engineering, a model representing the degree of formality and optimization of processes in an organization
• Developmental age, the age of an embryo as measured from the point of fertilization
• Mature technology, a technology has been in use and development for long enough that most of its initial problems have been overcome
• Maturity (finance), indicating the final date for payment of principal and interest
• Maturity (geology), rock, source rock, and hydrocarbon generation
• Maturity (psychological), the attainment of one's final level of psychological functioning and the integration of their personality into an organized whole
• Maturity (sedimentology), the proximity of a sedimentary deposit from its source
• Sexual maturity, the stage when an organism can reproduce, though this is distinct from adulthood