This paper introduces a three-stage split-crest (TSSC) technique for horizontal ridge augmentation in the atrophic posterior mandible. The first stage consists of splitting the ridge. Following a 3- to 4-week healing interval, the second stage consists of expansion of the cortical plate (without elevating the periosteum) and placement of a bone replacement graft material. After 3 to 4 months of healing, the implants are placed. The advantages of this three-stage technique are increased vascularization to the surgical area, a decrease in procedure complications, and improved implant survival rates. An extended treatment time is the main disadvantage. The purpose of this retrospective case series is to review and discuss a new step-by-step surgical procedure of a TSSC technique using a delayed implant placement protocol. The results, advantages, and limitations were also presented.