Maxillary nerve block is widely used for treating trigeminal neuralgia. Common complications of the procedure include bleeding and sensory abnormalities, but ophthalmic complications have been rarely reported. A 60-year-old woman underwent maxillary nerve block for refractory trigeminal neuralgia. Ten minutes after the procedure had ended, the patient reported double vision when she tried to turn the left eye outward. After examination, the patient was presumed to have diplopia due to the abducens nerve block. However, the symptom disappeared approximately 30 minutes later without any treatment. Thus, to prevent diplopia, the dose of local anesthetics should be reduced. Moreover, negative blood aspiration should be confirmed during the injection. To the best of our knowledge, this is the first case to report diplopia after maxillary nerve block without neurolysis through the lateral infrazygomatic approach.