This paper reports on the responses of 109 Australian mathematics teachers to an online questionnaire designed to identify their perceptions of the characteristics of quality professional learning (PL). They were asked to consider the best PL that they had ever undertaken, rate possible contributors to its quality on 5-point Likert type scales, select five features of quality PL that most contributed to the PL being the best they had experienced, and nominate any other factors that they believed contributed to it being the best ever. Teachers most valued PL that they considered to contribute to improved teaching and improved student learning. Nevertheless, the PL nominated was not necessarily characterised by all of the widely accepted features of effective PL. Implications for the conceptualisation of quality PL are discussed.