This study aimed to assess the compatibility of herbicides with Bacillus firmus, Purpureocillium lilacinum, Pochonia chlamydosporia, and Trichoderma harzianum, as well as their impact on Meloidogyne javanica. The experiments were conducted under a completely randomized design with nine treatments and five replicates. The treatments included control, diclosulam, sulfentrazone, flumioxazine, imazethapyr, S-metolachlor, pyroxasulfone, imazethapyr + flumioxazine, and glyphosate. For B. firmus, colony forming units per milliliter (CFU mL− 1) were counted; for fungi, the mycelial growth speed index (IVCM – mm day− 1) and percentage of inhibition were measured; and for nematodes, the mortality rate was determined. Results showed that imazethapyr, S-metolachlor, and glyphosate were incompatible with B. firmus. Regarding P. lilacinum, P. chlamydosporia, and T. harzianum, these herbicides, along with sulfentrazone, exhibited the highest inhibition percentages. The most significant mortality rates of M. javanica were observed with imazethapyr, flumioxazine, and S-metolachlor. In conclusion, S-metolachlor, imazetapyr, glyphosate, and sulfentrazone were identified as the least compatible with the tested biological nematicides.