Background: To address functional and smile dysfunction associated with post–facial paralysis synkinesis, the senior author (B.A.) has offered “modified selective neurectomy” of the lower division of the facial nerve as a long-term solution. This article examines technical considerations and outcomes of this procedure. Methods: A retrospective review was conducted of patients who underwent modified selective neurectomy of buccal and cervical branches of the facial nerve performed by a single surgeon over a 4½-year period. House-Brackmann facial grading scores, electronic clinician-graded facial function scale, and onabotulinumtoxinA (botulinum toxin type A) dosages were examined before and after the procedure. Results: Sixty-three patients underwent modified selective neurectomy between June 20, 2013, and August 12, 2017. There were no serious complications. The revision rate was 17 percent. Temporary oral incompetence was reported in seven patients (11 percent) postoperatively. A statistically significant improvement was achieved in electronic clinician-graded facial function scale analysis of nasolabial fold depth at rest, oral commissure movement with smile, nasolabial fold orientation with smile, nasolabial depth with smile, depressor labii inferioris lower lip movement, midfacial synkinesis, mentalis synkinesis, platysmal synkinesis, static score, dynamic score, synkinesis score, periocular score, lower face and neck score, and midface and smile score. There was a significant decrease in botulinum toxin type A dosage and House-Brackmann score after surgery. Conclusion: Modified selective neurectomy of the buccal and cervical divisions of the facial nerve is an effective long-term treatment for smile dysfunction in patients with post–facial paralysis synkinesis. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.