Motor skills are the basis for any bodily movement. They allow individuals to walk, write, interact with the environment, and participate in physical activity. These motor skills play a central role in lives of children and adults and specifically allow them to be physically active and healthy. As such, the ability to coordination movement is vital to our everyday lives and can influence the quality of life we experience. This thesis sought to examine the motor coordination processes in children and adults, and investigate how the factors of age and obesity influence these processes. Firstly, this thesis found that children’s fine motor skill proficiency fell below normative levels (Study 1) and that children’s sensory-motor integration was still developing at age 12 (Study 2). Further to this, given the extensive research showing that obese individuals demonstrate less proficient fine and gross motor skill competence than their normal- weight peers, this thesis also examined the effect of obesity on the motor coordination of adults. Results from studies 3 and 4 demonstrated that obese individuals were less able to accurately control and coordinate movements compared to their normal- weighted peers. Traditionally, these differences have been attributed to the mechanical implications of excess mass. However, given the limited influence of mass in fine motor skill tasks used in this series of studies, these findings further support the hypothesis that obese individuals experience sensory integration difficulties. If this is the case, the decreased perceptual-motor function might impede the performance of everyday life activities as well as their willingness to participate in physical activity. This offers new insight into the potential for decreased motor coordination to be a contributing factor to the increasing prevalence of obesity in children and adults.