Introduction: The prevention and management of neurocognitive disorders (NCD) among older adults can be improved by early identification of risk factors such as walking speed. The objective of the study is to assess the association between gait speed and NCD onset in a population of Peruvian older adults. Material and methods: Cohort conducted in older adults who attended the geriatrics service of Naval Medical Center (Callao, Peru). During the baseline assessment, participants’ gait speed was recorded. Subsequently, participants were followed-up annually for 5 years, with a mean of 21 months. NCD onset was defined as the occurrence of a score ≤ 24 points on the Mini Mental State Examination (screening test) during follow-up. The hazard ratios (HR) and their 95% confidence intervals (95% CI) were calculated using Cox regression. Results: The study included 657 participants, with a mean age of 73.4 ± 9.2 (SD) years, of whom 47.0% were male, 47.8% had a gait speed < 0.8 m/s, and 20.1% developed NCD during the follow up. It was found that older adults who had gait speed < 0.8 m/s at baseline were more likely to develop NCD than those who had a gait speed ≥ 0.8 m/s (adjusted HR = 1.41, 95% CI = 1.34-1.47). Conclusion: A longitudinal association was found between decreased gait speed and NCD onset, suggesting that gait speed could be useful to identify patients at risk of NCD onset.