In social situations, skillful regulation of emotion and behavior depends on efficiently discerning others' emotions. Identifying factors that promote timely and accurate discernment of facial expressions can therefore advance understanding of social emotion regulation and behavior. The present research examined whether trait mindfulness predicts neural and behavioral markers of early top‐down attention to, and efficient discrimination of, socioemotional stimuli. Attention‐based event‐related potentials (ERPs) and behavioral responses were recorded while participants (N = 62; White; 67% female; Mage = 19.09 years, SD = 2.14 years) completed an emotional go/no‐go task involving happy, neutral, and fearful facial expressions. Mindfulness predicted larger (more negative) N100 and N200 ERP amplitudes to both go and no‐go stimuli. Mindfulness also predicted faster response time that was not attributable to a speed‐accuracy trade‐off. Significant relations held after accounting for attentional control or social anxiety. This study adds neurophysiological support for foundational accounts that mindfulness entails moment‐to‐moment attention with lower tendencies toward habitual patterns of responding. Mindfulness may enhance the quality of social behavior in socioemotional contexts by promoting efficient top‐down attention to and discrimination of others' emotions, alongside greater monitoring and inhibition of automatic response tendencies.