The number of significant developments surrounding the GDPR since publication of the main volume of the Commentary in 2020 has been immense, and will make it necessary to publish a second edition in due course. In the meantime, we felt it would be useful to publish this update, which is designed to be read in conjunction with the main volume. It covers developments only between the last date of coverage of the Commentary (1 August 2019) and 1 January 2021 (with a few exceptions when it has been possible to take later developments into account). It is limited to selected Articles of the GDPR. This update is being made freely accessible on the internet with the kind permission of Oxford University Press. Full reference to it should be made if it is quoted from or paraphrased, as follows: C. Kuner, L.A. Bygrave and C. Docksey (eds.), The EU General Data Protection Regulation (GDPR): A Commentary – 2021 Update (OUP 2021).