This brief presents a real-life exampleof how a group of government decision-makers, programmemanagers, researchers and development partners workedtogether to improve the allocation of HIV resources in Sudanand thereby better address the HIV objectives that thecountry strives to achieve. The initial modelling analysisshowed that by reallocating funds towards antiretroviraltreatment (ART) and prevention programmes in Sudan, 37percent of new HIV infections could be averted with the sameamount of funding. These allocations combined withadditional technical efficiency gains would allow forincreasing ART coverage from 6 percent in 2013 to 34 percentin 2017, and more than double programme coverage for keypopulations. The reallocations in the 2015 to 2017 HIVbudget for the national response are projected to avert anadditional 3,200 new infections and 1,100 deaths in thesethree years compared to initially planned allocations.Thereallocations were achieved through a rigorous HIVallocative efficiency analysis and evidence-informed policyprocess, conducted by a multi-disciplinary team of nationaland international partners working for the common goal tomake Sudan’s HIV response more manageable and sustainable.The case study discusses process and outcomes of thiseffort. It also offers some reflections on the applicationof mathematical modelling to strengthening decision-makingof finite HIV resources, and some lessons learned about howto go ‘beyond modelling’ to application of modelledallocative efficiency improvements to improving actualbudget allocations for better health outcomes.