Introduction: Lentil (Lens culinaris Medik.) is a nutritionally rich legume widely cultivated across diverse agro-ecological zones. In Morocco, it is mainly grown by smallholder farmers under rainfed conditions on limited areas. The grain yield of lentil is strongly influenced by environmental variability, leading to genotype-by-environment interactions (GEI) that slow breeding progress. Understanding GEI interactions is critical for identifying high-yielding and stable genotypes to improve productivity. Methods: 40 lentil genotypes were evaluated across multiple field trials in major lentil-growing regions of Morocco. Trials were conducted under representative rainfed conditions with limited inputs. Grain yield data were collected, and the effects of genotype, environment, and their interaction were analyzed using appropriate statistical models to assess performance and stability. Results: Significant effects of genotype, environment, and GEI were observed for grain yield, indicating differential genotype performance across environments. Some genotypes exhibited consistently high yield and stability across environments, whereas others were more sensitive to environmental variation. The analysis allowed the identification of genotypes combining high productivity with broad adaptation. Conclusions: The study highlighted the importance of considering GEI interactions in lentil breeding under Moroccan conditions. High-performing and stable genotypes identified here represent promising candidates for enhancing lentil yield and supporting sustainable production. These findings provide valuable insights to increase genetic gain and guide future lentil breeding strategies in Morocco.