We reviewed a database of consecutive patients who had undergone acetabular reconstruction with the use of a custom 3D-printed implant with a dual-mobility bearing for the treatment of Paprosky type-3B defects between 2016 and 2019. Functional and radiological outcomes were assessed. A total of 26 patients (17 women and 9 men) with a minimum follow-up of 36 months (median, 53 months; range, 36 to 77 months) were identified. The median age at surgery was 69 years (range, 49 to 90 years), and 4 patients had pelvic discontinuity. The cumulative implant survivorship was 100%. The median Oxford Hip Score improved significantly from 8 (range, 2 to 21) preoperatively to 32 (range, 14 to 47) postoperatively (p = 0.0001). One patient had a transient sciatic nerve palsy, 1 hip dislocated 6 months postoperatively and was managed nonoperatively, and 1 infection recurred. No patient had a fracture. Radiographic evaluation showed bone ingrowth at the bone-implant interface in 24 patients (92%) at ≥12 months of follow-up and showed no evidence of implant loosening or migration at the latest follow-up (3 to 6 years). Excellent functional improvement, implant survivorship, and osseointegration were recorded in the patient cohort. Accurate preoperative planning and the adoption of custom 3D-printed implants showed promising results in complex revision hip surgery. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.