Introduction <p>Older adults with diabetes often experience a decline in locomotor functions, such as stair climbing and walking, which are important for activities of daily living (ADL). Furthermore, individuals with low Self-Efficacy for Locomotor Function (SELF) are at a higher risk of requiring locomotor assistance. This study explored the relationship between diabetes and SELF in older females.</p> Methods <p>This study included 45 females (15 non-diabetes, 30 diabetes) aged 65&#xa0;years and over without ADL impairment in our clinic. SELF was measured by walking and stair climbing. Physical function was measured by hand grip strength, knee extension force (KEF), and KEF divided by bodyweight (%KEF).</p> Results <p>The SELF of stair climbing was significantly lower in the diabetes mellitus group than in the non-diabetes mellitus group (<i>p = </i>0.009), whereas the SELF of walking was not significantly different (<i>p = </i>0.351). Diabetes status remained a significant factor in the SELF of stair climbing after adjusting for body mass index, orthopedic disease, and %KEF.</p> Discussion <p>Stair climbing is one of the most vigorous ADLs performed by older adults, and this result may be due to the fact that stair climbing is a more vigorous activity than walking. Furthermore, the results of this study suggest that other factors (physical function other than %KEF and handgrip strength, psychological factors) related to diabetes may be more important than %KEF in older females.</p> Conclusions <p>SELF for stair climbing in older females was lower in those with diabetes, indicating that diabetes status significantly influenced their perceived ability to perform this task.</p>