To support HTA agencies with consistent and pragmatic approaches, we have developed this best-practice guidance for the assessment of technologies for COVID-19. We focused on diagnostic and therapeutic technologies, as the most commonly assessed by HTA agencies. For therapeutics, we focused on treatments rather than post-exposure prophylaxis, however, the recommended approach is unlikely to be much different for prophylactic options. The recommendations herein are based on findings from a survey and workshop of HTA agencies, a workshop with health economic modellers, and reviews of COVID-19 methods guidance, clinical guidelines, and economic evaluations. They have also been discussed with, and refined with input from, a multi-stakeholder group at a policy sandbox event. The recommendations span several themes relevant to HTA, and some of the key proposals are summarised below. Foremost among them is the recommendation that the pandemic is used as an opportunity to implement a responsive, “living” approach to HTA.