Head MG, Brown RJ, Newell ML, et al. - Every year, billions of US$ are invested globally for infectious disease research and development. In present work, researchers sought to report on investments into infectious diseases research from funders in the G20 countries across an 18-year time period spanning 2000–17. They compared spending for different conditions and considering the global burden of disease to determine potential areas of relative underfunding. They searched research databases using a range of keywords and extracted open access data from funder websites. In the final 2000–17 dataset, 94,074 awards were included for infectious disease research, with a sum investment of $104·9 billion (annual range 4·1 billion to 8·4 billion) and a median award size of $257,176 (IQR 62 562–770 661). The highest amount of investment was recorded for HIV research relative to disability-adjusted life years (DALYs) burden. The lowest relative funding was recorded for scabies and syphilis. For high-threat pathogens (eg, Ebola virus and coronavirus), investments were frequently reactive and followed outbreaks. There was less evidence indicating that funding is proactively guided by global burden or pandemic risk. These findings show how research investments are assigned and how this links to disease burden and diseases with pandemic potential.