<p>This study aimed to evaluate the effects of molybdenum (Mo) and arbuscular mycorrhizal fungi (AMF) on soybean (Glycine max L. (Merr.) growth parameters, soil enzyme activities, AMF colonization, and spore densities under saline and non-saline soil conditions. The experiment included a control treatment along with three Mo doses (0%, 0.3%, and 0.6%) in both saline and non-saline soils. Additionally, AMF species from the <i>Glomus</i> genus (<i>G. intraradices</i>, <i>G. constrictum</i>, and <i>G. microcarpum</i>) were applied. The results showed that co-application of Mo (0.6%) and AMF increased plant growth parameters, including plant height (65.91%), stomatal conductanc (67.01%), SPAD value (18.45%), root lengt (48.67%), root fresh weight (2.58%), and root dry weight (22.15%) (<i>p</i> &lt; 0.01). Soil biochemical parameters, such as catalase (CAT:85.17%), urease (53.19%), and dehydrogenase (DHG:56.21%) activities, were also increased at 0.6% Mo + AMF application (<i>p</i> &lt; 0.01). The application of 0.6% Mo + AMF resulted in significant improvements (<i>p</i> &lt; 0.01) in soil and root mycorrhizal traits, particularly spore density (spores/g soil; 84.85%) and root mycorrhizal colonization intensity (M%; 27.63%). Overall, Mo + AMF applications substantially affected both plant and soil parameters. Among the treatments, 0.6% Mo + AMF showed the greatest synergistic effects, enhancing mycorrhizal colonization, enzyme activities, spore production, and overall plant growth. This studydoes not involveany human participants and is therefore not a clinicaltrial.</p><p><b>Trial registration</b></p>