Existential nihilism is a meaning-related worldview characterized by a rejection of the existence of meaning in life and a belief in the futility of trying to ameliorate this absence. Despite the rich but often ambiguous philosophical and cultural history of existential nihilism, its impact on mental health and society remains largely unknown due to a gap in the scientific measurement literature. To address this gap, an 8-item scale measuring the proposed construct was rigorously developed and tested in accordance with psychometric theory and scale development guidelines. Two identical studies were conducted within an undergraduate sample (N = 329) and a community sample (N = 307) to evaluate the scale's item quality, reliability, internal structure, convergent validity, concurrent validity, divergent validity, and incremental validity. Evaluation of the Existential Nihilism Scale (ENS) provided evidence of strong psychometric properties. This new measure promises to contribute to future research examining the impact of existential nihilism on mental health, wellbeing, and social outcomes.