Background/Objectives: Oral focal mucinosis (OFM) and solitary cutaneous focal mucinosis (SCFM) are rare, benign lesions characterized by localized mucin deposition in the stromal connective tissue. While both share similar histological features, they occur in distinct anatomical sites and clinical contexts and have not been directly compared in the literature. Method: This study presents a case series of 39 OFM cases diagnosed over 25 years, supplemented by a literature review of previously reported OFM cases, and compares the combined data with published cases of SCFM. The literature-based analysis included 116 OFM cases published in four articles and 138 cases of SCFM published in five articles. Demographic and clinical data were extracted and analyzed, including age, sex, lesion location, size, duration, symptoms, clinical impression, treatment, and recurrence. Results: The mean age of OFM patients was 41 years, with a slight female predominance, most commonly affecting the gingiva. SCFM cases were more common in males, with a higher mean age of 52 years and frequent occurrence on the extremities and trunk. Both lesions were predominantly asymptomatic and managed by conservative excision. Due to its rare occurrence and nonspecific clinical presentation, both entities were frequently clinically misdiagnosed. Conclusions: In conclusion, this is the first study to directly compare OFM with SCFM and represents the largest series of OFM reported to date. The study provides new comparative insights into SCFM and OFM, highlighting differences in age, gender, lesion site, size, and symptomatology. SCFM predominantly affects older males on the extremities, whereas OFM occurs in younger females, mainly in the gingiva, with larger, sometimes symptomatic lesions, and with a very low recurrence rate.