AimThe aim of this study was to investigate the non‐inferiority of alveolar ridge preservation (ARP) with membrane stabilization compared with non‐stabilization, focusing on changes of soft‐tissue contour in periodontally compromised extraction sockets. Secondary outcomes included changes in hard‐tissue contour, patient‐reported outcomes and new bone formation.Materials and MethodsTwenty‐four patients with periodontally compromised teeth were randomly assigned to ARP with (test group) or without (control group) membrane stabilization. To assess profilometric and hard‐tissue dimensional changes, dental impressions and cone beam computed tomography scans were performed at baseline (T0), immediately after ARP (T1) and 4 months post surgery (T2). Soft‐tissue healing in open healing sites was evaluated at T2, and wound closure was assessed 10 days post surgery. Patient‐reported outcomes were documented, and core biopsies were obtained for histomorphometric analysis.ResultsThe absolute profilometric horizontal width change at 3 mm below the crest in the test group was not inferior to that in the control group. For the relative values, horizontal width reduction (3 and 5 mm below the crest) and volumetric shrinkage (3–5 mm below the crest) were lower in the test group. No significant differences were observed in bone dimensional changes, wound healing, pain and swelling or histomorphometric outcomes.ConclusionARP with membrane stabilization in periodontally compromised extraction sockets is non‐inferior in terms of soft‐tissue contour changes to those without membrane fixation.Trial Registration: Clinical Research Information Service (CRIS), KCT0005280. Registered 4 August 2020, https://cris.nih.go.kr/cris/search/detailSearch.do?seq=19165&search_page=L