<p>Metal oxide nanoparticles (NPs) have attracted great attention for their potential to control pathogens. This study assessed the effects of silver oxide (Ag₂O) NPs, titanium dioxide (TiO₂) NPs, and their bulk counterparts on soybean development and the control of <i>Meloidogyne javanica</i>. Additionally, the effect of different doses of TiO₂ NPs and bulk TiO₂ was determined. Two greenhouse experiments were conducted, each comprising two trials (repetitions). In Experiment 1, seed treatment with Ag₂O NPs had no effect on nematodes. By contrast, TiO₂ NPs provided a mean reduction in nematode population density (number of nematodes per gram of root) of 52.97% in both trials, whereas their bulk counterpart achieved a 36.33% reduction. Soybean development was not influenced by treatment. In Experiment 2, five doses of bulk TiO₂ and TiO₂ NPs were tested (0, 125, 250, 500, and 1000 mg L⁻¹). No effect was observed for particle size, but dose effects were significant. In Trial 1, seed treatment led to a linear reduction in nematode number. In Trial 2, a maximum reduction of 69.90% was estimated to be achieved with 581.21 mg L⁻¹ TiO₂. Treatment positively influenced shoot height and dry weight in at least one of the trials, with the maximum values estimated to be achieved with doses of 545 and 533.33 mg L⁻¹, respectively. It is concluded that Ag₂O NPs have no effect on <i>M. javanica</i> in soybean, whereas adequate doses of TiO₂ NPs contribute to parasite control and soybean growth.</p>