Saudi Arabia has exceptional solar resources, rapidly growing electricity demand and a national commitment to energy diversification. The performance of photovoltaic systems, however, is affected by high module temperature, dust deposition, irradiance variability, equipment degradation, communication gaps and maintenance quality. Internet of Things monitoring can improve solar-energy harvesting by connecting field sensors, smart meters, inverters, weather stations and maintenance systems to a governed operational platform. This integrative review evaluates how IoT monitoring supports real-time performance assessment, fault detection, soiling management, predictive maintenance, energy forecasting and quality assurance in Saudi photovoltaic installations. It examines system architecture, sensor selection, communications, data quality, cybersecurity, analytics and human decision-making. The paper proposes a framework that converts trustworthy measurements into normalized performance indicators, diagnostic alerts, controlled work orders and verified energy outcomes. It emphasizes that connectivity alone does not optimize generation; benefits depend on calibrated instruments, appropriate baselines, reliable communications, interpretable analytics and timely field action. Black-box optimization without local validation can conceal sensor error or environmental effects. For Saudi Arabia, the recommended approach prioritizes temperature and soiling correction, geographically appropriate communication, secure integration with SCADA, and phased deployment across utility, industrial and distributed systems. The framework supports Vision 2030 through renewable-energy productivity, efficient operations, local technical capability and evidence-based asset management.