There is a limited information on the effects of Neltuma spp. on herbaceous species. This study assessed the effects of Neltuma spp. on herbaceous species in the drylands of northern Tanzania in 250 sampling quadrats established in the invaded and uninvaded areas. In each quadrat, information on herbaceous species composition, abundance, basal cover, and diversity was collected and compared between the two areas using Generalized Linear Mixed Models. Non-metric Multidimensional Scaling and Indicator Species analyses were applied to visualize patterns in species composition and identify species significantly associated with invaded and uninvaded areas, respectively. Results revealed that herbaceous species abundance, basal cover, and diversity were significantly (p < 0.001) lower in invaded areas compared to uninvaded areas. Soil moisture had a significant (p < 0.05) positive effect on herbaceous species. Species composition differed substantially between invaded and uninvaded areas. Digitaria velutina, Eragrostis superba, Eriochloa fatmensis, Pennisetum mezianum, and Indigofera atriceps were indicators of uninvaded areas, while Tragia insuavis was the indicator of invaded areas. Indicator species from uninvaded areas provide important socio-economic benefits. The continuing spread of Neltuma spp. threatens the sustainability of these benefits, calling for targeted management to curb their spread and preserve ecosystem functions in affected drylands.