Only a few studies investigated inhibition in people with Down syndrome (DS) considering inhibitory sub-components. This study investigates interference suppression, through global-local processes, in 51 people with DS matched for mental age with 71 typically developing children. We adapted and administrated a non-verbal Navon-shape task, composed by high-familiarity symbols. Results showed for both groups equal performances on global and local conditions with congruent stimuli, whereas better performances on global condition when they had to respond to incongruent items. For both groups a greater impairment in incongruent responses emerged and more so for people with DS.