A single administration of cannabidiol (CBD) can reduce anxiety during social anxiety inductions. No study, however, has evaluated the impact of CBD on fear responding among humans. A double-blind, randomized, placebo-controlled trial was undertaken to address this gap in the literature. Specifically, the current study tested a single oral administration of CBD (either 150mg, 300mg, or 600mg), compared to placebo, for reducing fear reactivity to a well-established 5-min administration of 10% carbon dioxide (CO2)-enriched air biological challenge. CBD was administered 90min prior to the challenge. Participants were 61 healthy young adults who self-reported fear continuously during the challenge. Heart rate also was continuously monitored, and panic symptoms were self-reported using the Diagnostic Sensations Questionnaire immediately following the procedure. Results indicated no effect of condition on self-reported fear, panic symptoms, or heart rate. This is the first study to document that CBD does not reduce fear reactivity in humans, thereby representing an important extension to research on the effects of CBD.