Abstract Objectives The development of sialolithiasis is commonly related to local factors, such as the retrograde migration of foods, bacteria, or foreign bodies from the oral cavity. The association of sialolithiasis and saliva stasis resulting from decreased spontaneous secretion remains largely unexplored. The current study investigated the potential role of impaired spontaneous secretion in association with the formation of submandibular gland calculi. Study Design A retrospective cohort study. Methods Between September 2016 and December 2017, 11 patients with unilateral submandibular gland sialolithiasis confirmed with sialendoscopy were assigned to the experimental group. Another 35 patients clinically diagnosed with parotid obstructive sialadenitis were assigned as the control group. The slope changes of the isotope count curve of the unaffected submandibular gland in the experimental group and the bilateral submandibular glands in the control group were calculated and compared to estimate the spontaneous secretion differences. The degree of spontaneous secretion was defined as the slope changes in the steady ascending stage of the scintigraphic exam. Results The slope decline (degree of spontaneous secretion) on the unaffected side in patients with single-gland submandibular obstructive sialadenitis was significantly lower than that in the control individuals (p = .002). In contrast, the between-group comparison in the unaffected parotid glands revealed no difference in the slope decline. Conclusion The spontaneous secretion of the submandibular gland in patients with submandibular sialolithiasis was decreased compared to that in patients without submandibular sialolithiasis. This phenomenon might be associated with the development of sialolithiasis. Level of Evidence 3.