Like several other revenue administrations, prior to the introduction of the Tax Administration Diagnostic Assessment Tool (TADAT) in Uganda, there was no comprehensive standard tool for assessing revenue administration against internationally recognised good practices. Detailed assessment was spread across different facets of revenue administration and indicators were not standardised. The first TADAT assessment of Uganda’s tax administration was conducted in 2015, and the Uganda Revenue Authority (URA) resolved to adopt the TADAT framework in order to improve organisational performance. This study considers the extent to which TADAT standards have been effective in improving the URA’s tax administration, and discusses key challenges and lessons learnt. It is largely qualitative, with data collected from URA staff through questionnaires, interviews and focus group discussions.