Background <p>The relationship between Klotho, blood glucose levels, and cognitive function is well-established. However, limited data exist on the association between Klotho and cognitive function in diabetes individuals.</p> Objective <p>To investigate the potential link between serum Klotho levels and cognitive function in diabetes individuals.</p> Methods <p>Using data from the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2014, we employed generalized linear regression to assess the correlation between serum Klotho levels and cognitive function in diabetes individuals. Furthermore, a restricted cubic spline (RCS) analysis was conducted to explore the relationship, with stratified analyses by sex.</p> Results <p>Our study included a total of 514 individuals. Serum Klotho levels were positively correlated with DSST cognitive test scores (β = 0.31, <i>P</i> &lt; 0.05, P-non-linear = 0.041) and overall cognitive scores (β = 0.83, <i>P</i> &lt; 0.01, P-non-linear = 0.8001) in diabetes individuals. Subsequent sex-stratified analysis revealed significant correlations, particularly in females, where an inverted U-shaped curve was observed between Klotho and DSST cognitive test scores, with a turning point at Ln(Klotho) of 6.766 pg/mL.</p> Conclusion <p>Elevated serum Klotho levels in diabetes individuals were associated with higher cognitive function, with this association being particularly significant in females. This study provided new evidence regarding sex differences in the association between Klotho levels and cognitive function in diabetes individuals.</p>