Soil salinization poses a major challenge to irrigation efficiency by intensifying upward evaporative fluxes and promoting salt accumulation in the root zone, thereby impairing water use efficiency (WUE) and crop yield. Subsurface drip irrigation (SSDI), compared to surface drip irrigation (SDI), has been proposed as a strategy to mitigate these constraints, but its effectiveness across diverse environmental and management settings is still unclear. We synthesized evidence from 61 field experiments conducted in arid and semi-arid regions on major dryland crops (e.g., cotton, maize, and wheat) and found that SSDI reduced soil salinity by 3.6 % while increasing WUE and yield by 15.0 % and 9.9 %, respectively, indicating a practically meaningful improvement in irrigation productivity under water-limited, salinity-prone conditions. These benefits were more pronounced in salttolerant crops, especially under arid conditions with sandy soils and high evaporative demand. However, rising irrigation water salinity weakened the desalinization effect but further enhanced the relative gains in WUE and yield. System design and management practices strongly influenced outcomes. Deep burial (>25 cm), surface mulching, and full to moderate irrigation quotas optimized performance. While desalination effects tended to diminish after 2-3 years, improvements in WUE and yield were sustained over time. However, SSDI adoption may be constrained by higher installation and maintenance requirements, and sustained management is likely necessary to maintain system performance and salinity control over the long term. Overall, yield gains under SSDI were primarily mediated by enhanced WUE rather than direct salinity reduction. These findings provide quantitative guidance for designing and managing SSDI systems under saline and water-limited conditions.