Squamous cell carcinoma makes up 90% of cases of oral cancer. However, a myriad of premalignant, inflammatory, and immune-based conditions can manifest as oral mucosal lesions. Biopsy of these lesions shares many of the principles of cutaneous lesions. Biopsy of oral mucosal lesions is a procedure that is safely performed in most cases in the outpatient ambulatory setting using local anesthesia. Special considerations should be taken depending on the presumed diagnosis based on physical examination. Its clinical relevance depends on a sound clinicopathologic assessment of the patient’s condition. This article reviews specific considerations for biopsy of oral mucosal lesions.