AbstractAppropriate irrigation water management has attracted a considerable degree of attention because it is crucial to guarantee water and food security worldwide. A smart irrigation system is applied for the rational use of water in agricultural fields and for maximizing crop yield. Thus, the high demand for water resources is decreased, and the adverse environmental impacts of irrigation are reduced. Different irrigation approaches were developed to reduce overirrigation by assessing the soil moisture content or crop water stress index. This paper aims to review conventional and smart irrigation technologies and discuss their effect on water savings, yield, and crop quality. The analysis of prominent studies highlighted that the water use efficiency based on soil moisture sensors depends on the volumetric moisture content threshold value set by farmers. Soil moisture sensor controllers, evapotranspiration controllers, and rain sensors have been shown to save 20%–92%, 20%–71%, and 7%–50% of water, respectively, while maintaining crop growth and quality. The optical sensor‐based system showed a better ability to assess crop and soil variability in the field than the on‐site measurements. The conventional controlled deficit irrigation technique was found to decrease the crop yield to less than 25% with water savings of up to 13%.