Chronic sclerosing sialadenitis (CSS), currently included in the group of immunoglobulin G4 (IgG4)-related diseases, is an under-recognized inflammatory lesion that afflicts mostly the submandibular gland of 40–60 years adults. To our knowledge, only one case of CSS located in the submandibular gland has been reported in childhood to date. We present a case of CSS in a 5-year-old male child. He presented with bilateral submandibular swellings that clinically resembled discrete lumps, suspected to be tumors. The completely resected tumors composed predominantly of dense lymphoplasmacytic inflammatory infiltrate rich in IgG4-positive cells [77–90 IgG(+) cells per high-power field; IgG4(+)/IgG(+) cells ratio of 42.77%]. We discuss the peculiarities of this case, and we also review the literature on CSS.