Martyrdom is defined as the psychological readiness to suffer and sacrifice one�s life for a cause. An integrative set of 8 studies investigated the concept of martyrdom by creating a new tool to quantitatively assess individuals� propensity toward self-sacrifice. Studies 1A�1C consisted of psychometric work attesting to the scale�s unidimensionality, internal consistency, and temporal stability while examining its nomological network. Studies 2A�2B focused on the scale�s predictive validity, especially as it relates to extreme behaviors and suicidal terrorism. Studies 3�5 focused on the influence of self-sacrifice on automatic decision making, costly and altruistic behaviors, and morality judgments. Results involving more than 2,900 participants from different populations, including a terrorist sample, supported the proposed conceptualization of martyrdom and demonstrated its importance for a vast repertoire of cognitive, emotional, and behavioral phenomena. Implications and future directions for the psychology of terrorism are discussed. (PsycINFO Database Record (c) 2014 APA, all rights reserved)