Background <p>Maternal caregiving for children with developmental disabilities is associated with substantial physical and psychosocial demands that may affect cognitive functioning. This study aimed to investigate factors associated with cognitive function among mothers of children with developmental disabilities using a cross-sectional design.</p> Methods <p>This cross-sectional study included 179 mothers of children with developmental disabilities. Sociodemographic characteristics were recorded. Musculoskeletal pain distribution was assessed using the Nordic Musculoskeletal Questionnaire (NMQ), and maternal pain intensity was evaluated with the Visual Analogue Scale (VAS). Cognitive function was assessed using the Montreal Cognitive Assessment (MoCA). Physical activity level, hopelessness, and sleep quality were evaluated using the International Physical Activity Questionnaire–Short Form (IPAQ-SF), Beck Hopelessness Scale (BHS), and Pittsburgh Sleep Quality Index (PSQI), respectively.</p> Results <p>MoCA total score was significantly correlated with maternal age (<i>r</i> = -0.273), maternal education duration (<i>r</i> = 0.513), number of children (<i>r</i> = -0.300), child’s age (<i>r</i> = -0.341), BHS total score (<i>r</i> = -0.581), IPAQ-SF total score (<i>r</i> = 0.581), and maternal pain intensity (<i>r</i> = -0.357) (all <i>p</i> &lt; 0.05), but not with PSQI total score (<i>r</i> = 0.080, <i>p</i> &gt; 0.05). In hierarchical regression analysis, education duration, physical activity level, hopelessness, and child’s age remained independently associated with maternal cognitive function in the final model (R² = 0.623, <i>p</i> &lt; 0.001).</p> Conclusion <p>Longer maternal education duration, higher physical activity levels, lower hopelessness, and younger child age were associated with better cognitive function among mothers of children with developmental disabilities. These findings highlight potentially modifiable factors related to maternal cognitive health in this population.</p>