Inadequate health-care provider performance is a major challenge to the delivery of high-quality health care in low-income and middle-income countries (LMICs). The Health Care Provider Performance Review (HCPPR) is a comprehensive systematic review of strategies to improve health-care provider performance in LMICs. We screened 216,477 citations and selected 670 reports from 337 studies of 118 strategies. For professional health-care providers (generally, facility-based health workers), the effects were near zero for only implementing a technology-based strategy or only providing printed information. For percentage outcomes, training or supervision alone typically had moderate effects (10·3–15·9 percentage points), whereas combining training and supervision had somewhat larger effects than use of either strategy alone. Group problem solving alone showed large improvements in percentage outcomes (28·0–37·5 percentage points), but, when the strategy definition was broadened to include group problem solving alone or other strategy components, moderate effects were more typical (12·1 percentage points).