The oscillatory baffled reactor has been well-characterised in most areas of flow reactor performance (mixing, mass transfer, multi-phase operation etc.), with the exception of heat transfer, where comparatively few data exist in the literature. Here, a robust investigation of heat transfer in the "standard", 26 mm diameter, oscillatory baffled reactor is presented which goes beyond the parametric limitations of previous studies. 5-fold Nusselt number increases over steady unbaffled flows are shown to be achievable. The maximum enhancement attributed to the oscillatory flow component alone compared to the steady-flow, baffled case is shown to be 1.7-fold. The degree of heat transfer enhancement is shown to plateau when the oscillatory flow Reynolds number exceeds 1300, indicating that a radial mixing limit has been reached. A new correlation for predicting heat transfer coefficients in oscillatory baffled reactors has been developed. Based on the data generated here, it is accurate to 30% across the experimental range of the study. The correlation has been further validated using literature data, and shown to be the most robust correlation to date for predicting heat transfer performance in oscillatory baffled reactors.