This study describes the effect of passive lingual arch space maintainer appliance on mandibular dental arch growth in early mixed dentation period after bilateral loss of primary molars. Materials : Mandibular dental arch growth were measured and monitored in thirteen children included into two treatment groups, lingual arch group with 20 cases, and bilateral band and loop group with 10 cases. Children were evaluated every six monthfor eighteen months using study cast for growth change in intermolar width, intercanine width, and arch perimeter. Results: Mandibular growth parameters in both groups increased significantly with time with no statistically significant difference in growth of mandibular intercanine width, intermolar width and arch perimeter between both groups. Conclusions:lingual arch space maintainer did not significantly affect growth of mandibular dental arch.