Lectin receptor-like kinases (LecRLKs) are membrane-bound receptor genes found in many plant species. They are involved in perceiving stresses and responding to the environment. Oat (Avena sativa; 2n = 6x = 42) are an important food and forage crop with potential in drought, saline, or alkaline soils. Here, we present a comprehensive genome-wide analysis of the LecRLK gene family in A. sativa and the crop’s wild relatives A. insularis (4x) and A. longiglumis (2x), unveiling a rich diversity with a total of 390 LecRLK genes identified, comprising 219 G-types, 168 L-types, and 3 C-types in oats. Genes were unevenly distributed across the oat chromosomes. GFP constructs show that family members were predominantly located in the plasma membrane. Expression under salt stress demonstrated functional redundancy and differential expression of LecRLK gene family members in oats: 173 members of this family were involved in the response to salt stress, and the expression levels of three C-type genes in the root and leaf were significantly increased under salt stress. The results show the diversity, evolutionary dynamics, and functional implications of the LecRLK gene family in A. sativa, setting a foundation for defining its roles in plant development and stress resilience, and suggesting its potential agricultural application for crop improvement.