An 11-week growth trial was conducted to determine dietary myo-inositol (MI) requirement for juvenile gibel carp (Carassius auratus gibelio). Myo-inositol was supplemented to the basal diet to formulate six purified diets containing 1, 56, 107, 146, 194 and 247 mg MI kg−1 diet, respectively. Each diet was fed to triplicate groups of juvenile gibel carp (initial body weight 3.38 ± 0.27 g, mean ± SD) in a flow-through system. The diets were randomly assigned to different fish tanks. Fish fed ≥ 107 mg MI kg−1 diet had significantly higher weight gain (WG), feed efficiency (FE) and protein efficiency ratio than those fed 1 mg MI kg−1 diet. Fish fed ≥ 56 mg MI kg−1 diet had higher feeding rate and survival compared with fish fed 1 mg MI kg−1 diet. Dietary supplemental inositol did not affect fish liver inositol concentration. Fish fed ≥ 56 mg MI kg−1 diet had higher body dry matter, crude protein and gross energy and lower hepatosomatic index than fish fed 1 mg MI kg−1 diet. Dietary inositol supplementation decreased fish body ash. Quadratic regression of weight gain indicated that the myo-inositol requirement to maximum growth for juvenile gibel carp was 165.3 mg MI kg−1 diet.