Background: Walk tests are common gait speed and endurance assessments. Shorter test versions could benefit adults with intellectual disability. Thus, the concurrent validity of shorter tests was studied. Methods: Thirty-five adults with mild to moderate intellectual disability, aged 21-64 years, were assessed with the 4-m walk test, 10-m walk test for gait speed, 2-min walk test, and 6-min walk test for endurance. Correlation and Bland--Altman plots analyses were used to establish concurrent validity between shorter and standard tests. Results: Strong positive relationships were found for gait speed tests, r = 0.94, p < 0.001, and endurance tests, r = 0.83, p < 0.001, and differences between shorter and standard tests were within limits of agreement. Conclusions: The concurrent validity of shorter walk tests was established in this study. This would mean that adults with intellectual disability with lower levels of fitness could be assessed.