Peer observation of teaching is an established developmental tool in face-to-face settings. While there have been studies into peer observation as applied to asynchronous online teaching, less is known about its application to teaching online using synchronous communication systems. We describe a small-scale study of an online peer observation scheme with a group of associate lecturers in physical sciences at the UK Open University. This cohort of teaching staff was engaged in a series of peer-observed tutorials, with the aim of fostering their development through subsequent reflection and dialogue. The study was evaluated through the thematic analysis of subsequent structured conversations. Emergent themes lead us to consider the value of peer observation in the context of synchronous online tuition.