Penology is a sub-component of criminology that deals with the philosophy and practice of various societies in their attempts to repress criminal activities, and satisfy public opinion via an appropriate treatment regime for persons convicted of criminal offences.

The Oxford English Dictionary defines penology as "the study of the punishment of crime and prison management," and in this sense it is equivalent with corrections. The term penology comes from "penal", Latin poena, "punishment" and the Greek suffix -logia, "study of".

Penology is concerned with the effectiveness of those social processes devised and adopted for the prevention of crime, via the repression or inhibition of criminal intent via the fear of punishment. The study of penology therefore deals with the treatment of prisoners and the subsequent rehabilitation of convicted criminals. It also encompasses aspects of probation (rehabilitation of offenders in the community) as well as penitentiary science relating to the secure detention and retraining of offenders committed to secure institutions.

Penology concerns many topics and theories, including those concerning prisons (prison reform, prisoner abuse, prisoners' rights, and recidivism), as well as theories of the purposes of punishment (deterrence, retribution, incapacitation and rehabilitation). Contemporary penology concerns itself mainly with criminal rehabilitation and prison management. The word seldom applies to theories and practices of punishment in less formal environments such as parenting, school and workplace correctional measures.