<p>Rapid urbanization in Ethiopia is intensifying pressure on urban green spaces, affecting biodiversity, ecosystem services, and human well-being. This systematic review analyzed 26 studies published between 2011 and 2024 that quantified biodiversity and/or carbon stocks in urban forests, church forests, parks, institutional greens, home gardens, and street-tree systems. Reported woody species richness varied widely, urban forests ranged from 22 to 176 species, church forests commonly reported 90 species, and home gardens ranged from 36 to 66 species across the reviewed urban studies. Carbon stocks likewise spanned large ranges and were sensitive to whether below-ground and soil pools were quantified. When all pools were reported, total ecosystem carbon stocks (TECS) reached ~ 296 t ha⁻¹ in Addis Ababa parks; above- plus below-ground biomass carbon in Addis Ababa urban forests summed to ~ 171 t ha⁻¹; institutional greens in Hawassa reported TECS of ~ 187 t ha⁻¹; and street-tree corridors with measured soil pools reached ~ 265 t ha⁻¹. Home gardens stored ≥ 64 t ha⁻¹ in above-ground biomass in Dilla town. Evidence on street trees remains comparatively sparse. Collectively, this synthesis shows that Ethiopian UGIs deliver measurable biodiversity and carbon co-benefits, with magnitudes shaped by protection status, stand structure, and management. The review highlights gaps in standardized carbon accounting (especially for BGBC and SOC) and street-tree inventories, while emphasizing the need to conserve remnant forests, diversify plantings with native species, and implement consistent monitoring across cities.</p>