A TeachMeet is an informal gathering arranged by teachers to share and discuss practice with peers in a social setting. This paper focuses on reporting one fundamental finding of an in-depth exploration of TeachMeet, relating to the characteristics of the events; other findings are reported independently. TeachMeet originated in 2006, adopting participant-driven unconference practices and exploiting emergent social media channels and becoming a global phenomenon. This paper reports findings from a sensemaking exploration of TeachMeet events (n. = 15) in which analysis of data from observations highlighted elements most commonly present, which characterise the events. Data collected were analysed using Descriptive Statistics and Interpretative Phenomenological Analysis. This analysis found TeachMeets to be voluntary, open, non-hierarchical events attended by teachers from all levels and sectors, during which the three characteristic elements at play were (i) the catalytic role of the facilitator, (ii) the impact of nanopresentations, and (iii) the Open Space dynamic. The element of connectivity via social media was influential during and between events. We conclude that these elements in combination characterise this novel phenomenon for informal open professional learning among peers, at gatherings convened by and for teachers to share their experiences in the convivial setting of a TeachMeet.