Deradicalization of terrorists constitutes a critical component of the global “war on terror.” Unfortunately, little is known about deradicalization programs, and evidence for their effectiveness is derived solely from expert impressions and potentially flawed recidivism rates. We present the first empirical assessment of one such program: the Sri Lankan rehabilitation program for former members of the Liberation Tigers of Tamil Eelam (a terrorist organization that operated in Sri Lanka until their defeat in 2009). We offer evidence that deradicalization efforts that provided beneficiaries with sustained mechanisms for earning personal significance significantly reduced extremism after 1 year (Study 1). We also found that upon release, beneficiaries expressed lower levels of extremism than their counterparts in the community (Study 2). These findings highlight the critical role of personal significance in deradicalization efforts, offer insights into the workings of deradicalization, and suggest practical methods for improving deradicalization programs worldwide.