This paper evaluates Uganda’s three-decade effort (1990-2021) to “sow” tax reforms and “reap” higher domestic revenue. Combining
administrative data, policy chronologies and counterfactual analysis, we identify three reform waves: (i) 1991-1997—creation of the
Uganda Revenue Authority (URA), introduction of the VAT and a new Income Tax Act that lifted the tax-to-GDP ratio from 6.5 % to
12.2 %; (ii) 2004-2012—large-taxpayer segmentation, automation and taxpayer education that raised nominal revenue by 317 % but

failed to raise the tax-to-GDP ratio above 13 %; and (iii) 2013-2021—piecemeal rate adjustments, digital e-services levies and the
Domestic Revenue Mobilisation Strategy aimed at a 16-18 % target that remains elusive at 12-14 % of GDP. Event-study estimates
show that each wave initially added 0.5-1.0 percentage points of GDP in new revenue, but gains eroded within five years as
exemptions widened and compliance plateaus were reached. Difference-in-differences against a synthetic control suggest Uganda
collected an extra USD 5.4 bn (cumulative, 2010 prices) relative to a no-reform scenario, yet the tax gap still exceeds 5 % of GDP.
Structural breaks coincide with political business cycles: revenue jumps during high-ownership periods (1991-1997, 2004-2012) and
flattens when discretionary exemptions rise. Qualitative evidence links sustained gains to bureaucratic autonomy, while reversals
follow politicised tax holidays and erosion of real excise rates. The findings imply that “sowing” administrative capacity yields quicker
harvests than perpetual rate tinkering, and that Uganda’s next growth spurt in domestic revenue will require not new taxes, but
credible closure of loopholes and a political compact against exemptions.