Throughout the 20th and 21st centuries, as the number of detainees in Iran’s prisons has steadily increased, members of first the Pahlavi and now the Islamic Republic governments have promised that carceral methods – surveillance, policing, and especially prisons – would render Iranians safer from the social scourge of crime. This paper analyzes the methods by which mass criminalization and mass carceralization — in other words, the surveillance and categorization of everyone in Iran into categories of relative criminality, and the incarceration of increasing exponential numbers of people — came to be seen in Iran as obvious and necessary modern (and eventually Islamic) responses to a wide host of social issues, including drug use, sex work, border crossing, and more. In the mid-20th century, in part in response to rising public concern over female and child criminality, the Pahlavi elite began to heavily promote the rehabilitative capacity of their newly built prison system, claiming that these prisons would help transform social deviance into social productivity, perhaps even ending crime altogether. The names of Iran’s prisons were changed in the 1960s to reflect this rehabilitative impulse; the Central Prison for Men and Women [Zendan-e Markazi-ye Mardan va Zanan] was changed to Penitentiary (or place of repentance) for Men and Women [Nedamatgah-e Mardan va Zanan], while some prisons stopped using the word prison [zendan] altogether and instead called themselves Place of Counsel [andarzgah]. Indeed, government officials both before and after the 1979 revolution in Iran, despite using different languages and moral logics, have both argued that their prisons could reform the incarcerated from bad criminals into good citizens. Beginning with a brief overview of policies founded by the Pahlavi government — including prison labor and education programs — this paper traces the idea promoted both before and after the 1979 revolution that increased policing and incarceration was a rehabilitative strategy meant to address and even cure the “disease” of criminal activity. This paper also examines recent efforts in the Islamic Republic to decrease the numbers of those held in traditional carceral sites (that is, prisons) by the use of different forms of carceral control — biotechnology, ankle monitors, facial recognition software, digitized border surveillance, etc., arguing that the making of the carceral imagination in Iran has always been and remains a fundamentally global project.