IntroductionAlthough meditation practice encompasses both intrapersonal and interpersonal dimensions, the differential effects of individual versus group meditation settings (IS vs. GS) remain largely unexplored. This study aimed to reduce this gap by comparing the effects of a mindfulness meditation session performed in the two settings, focusing in particular on mind-wandering (MW) dynamics.MethodsExpert meditators (n = 30) performed two 30-min breath-focused mindfulness meditation sessions, one in IS and one in GS. During the meditations, participants reported the occurrence of MW via button presses. After each meditation, participants completed questionnaires assessing state mindfulness, mood, and meditation-related experiences. Trait-like questionnaires were also collected.ResultsAcross the two meditation settings, the average number of MW self-reports was similar, but their temporal course was significantly different: the rate of MW reports per time remained almost constant over time in IS, whereas it slightly increased in GS. Moreover, lower scores were observed in GS than in IS for the mood states of tension–anxiety and fatigue–inertia.DiscussionThe present study showed that the temporal dynamics of MW during mindfulness meditation differed depending on the meditation setting. The study also showed that, on average, meditating in a group allowed expert mindfulness practitioners to feel less tired/inert and less tense/anxious at the end of the session compared with meditating individually. Although preliminary, these findings hint at why complementing individual mindfulness practice with group sessions may be useful, for example, when practitioners experience difficulties maintaining a regular practice.