["Autism Research, Volume 19, Issue 4, April 2026. ", "\nABSTRACT\nAlthough motor‐skill differences in autistic individuals are well established, there is diverging evidence regarding what happens to motor skills in autistic children as they become adolescents. Using both cross‐sectional and longitudinal data, we examined fine and gross motor skills and grip strength of 187 autistic participants and 136 non‐autistic participants (i.e., with no known diagnoses), aged 6–18 years‐old. Participants completed the Bruininks‐Oseretsky Test of Motor Proficiency‐Short Form, Second Edition (BOT‐2 SF), and maximal grip strength testing. Linear mixed‐effects regression analyses indicated motor‐skill differences between autistic and non‐autistic participants across this age range; however, the nature of these differences depended on the specific motor domain (i.e., strength) and measure. Specifically, grip strength and BOT‐2 SF strength subtest scores showed widening group differences with increasing age, whereas overall BOT‐2 SF scores and subtests showed sustained or narrowing group differences through adolescence. However, items on the BOT‐2 SF also demonstrated substantial ceiling effects, which may obscure later group differences between autistic and non‐autistic participants and highlight the need for measures that encompass a greater range of motor skills into adolescence. These findings have important implications for healthcare, education, and community supports that address age‐related motor differences within the autistic population.\n"]