Freshwater scarcity already affects approximately 38% of global croplands, making full irrigation with freshwater increasingly impractical. To address this challenge, deficit irrigation (DI) using saline water has emerged as a water-conserving strategy in agriculture, particularly in tree orchards. However, this strategy may increase soil salinization and reduce yields, raising concerns about its long-term sustainability. This review analyses current knowledge on soil salinization risks associated with saline DI in orchard systems, aiming to support water conservation through safe and effective management practices. Three key insights emerge. First, while saline DI can reduce freshwater use in orchards by up to 50%, yield reductions of up to 24% may occur due to the combined effects of water deficit and soil salinization, particularly where salt leaching is insufficient or water deficit levels are severe. Second, natural factors such as rainfall, even in small amounts, and soil textures that favor leaching play a crucial role in mitigating soil salinization risks under DI. Finally, sustainable use of saline water for DI requires careful management, including optimized irrigation scheduling, efficient irrigation methods (particularly drip irrigation), adequate salt leaching, and supplementary water management practices such as rainwater harvesting. Collectively, these insights support the proper management of soil salinization risks in orchards while promoting sustainable water conservation and long-term productivity. They can also contribute to achieving the United Nations Sustainable Development Goals by enhancing food security (SDG 2), improving water-use efficiency and safeguarding freshwater resources (SDG 6), and fostering more sustainable production systems (SDG 12).