Purpose: Alveolar ridge preservation procedures have been advocated to minimize postextraction dimensional loss. There is a need for systematic analyses of clinical factors affecting the outcomes of these procedures in order to improve their clinical outcomes. This systematic review and meta-analysis aimed to assess the efficacy of alveolar ridge preservation procedures in terms of hard tissue dimensional changes and to determine clinical factors affecting outcomes of these procedures. Materials and Methods: Studies comparing alveolar ridge preservation procedures with tooth extraction alone that reported quantitative outcomes for hard tissue dimensional changes were included. The primary outcome variable was horizontal dimensional changes of alveolar bone. Subgroup analyses evaluated effects of wound closure, flap elevation, type of grafting materials, use of barrier membranes, use of growth factors, socket morphology, and the position of teeth on outcomes of alveolar ridge preservation procedures. Results: Twenty-one studies were included, and quantitative analyses were performed for seven outcome variables. Significant differences between alveolar ridge preservation and control sites were found for six outcome variables, all favoring alveolar ridge preservation procedures. The magnitude of effect for the primary outcome variable (horizontal dimensional changes of alveolar bone) was 1.86 mm (95% CI = 1.44, 2.28; P .001). This magnitude of effect for the primary variable (as determined by subgroup analysis) was also significantly affected by type of wound closure (P = .033), type of grafting materials (P = .001), use of barrier membranes (P = .006), use of growth factors (P = .003), and socket morphology (P .001). Conclusion: Alveolar ridge preservation procedures are effective in minimizing postextraction hard tissue dimensional loss. The outcomes of these procedures are affected by morphology of extraction sockets, type of wound closure, type of grafting materials, use of barrier membranes, and use of growth factors. Schlagwörter: alveolar ridge augmentation, alveolar ridge preservation, bone augmentation procedures, dental implants, evidence-based dentistry, meta-analysis, socket healing, tooth extraction