Selenium (Se) is an essential micronutrient for human health, playing a crucial role as a component of various enzymes and proteins involved in antioxidant defense and immune regulation. In small quantities, Se can improve plant yield and quality and modulate stress-responsive genes [1-3]. However, plant foods grown in Se-deficient soils inevitably contain low levels of this micronutrient. This study aimed to address this issue by biofortifying pea microgreens (Pisum sativum L.) under heat stress through seed priming with Se. Seed priming is a cost-effective and environmentally friendly method for biofortifying edible crops, promoting uniform germination and fast emergence, even under stressed environments. In this experiment, seeds were submitted to nutri-priming treatments using 25–100 µM Se solutions for 6 and 12 h, with sodium selenate as the Se source. Hydroprimed and unprimed seeds served as controls. After treatment, one batch of seeds was tested for electrolyte leakage, while another was grown in a high-temperature greenhouse to produce pea microgreens. Emergence rate and morphological parameters were monitored daily. Upon harvest, biomass was measured, and the Se content was analyzed by atomic absorption spectrometry. Additionally, chlorophyll levels, soluble sugars, organic acids, total phenolics, and antioxidant activity were quantified using different analytical methods [4]. The seed treatment significantly influenced the emergence and growth of pea microgreens. The 6 h treatment resulted in superior agronomic performance and greater biomass accumulation compared to the 12 h treatment. However, the unprimed control exhibited the highest emergence rate. Despite this, Se priming significantly increased the Se concentrations in the microgreens' aerial parts, confirming the effectiveness of this biofortification strategy. These findings highlight the need to balance biomass production with Se accumulation to optimize production protocols under heat stress, contributing to the development of Se-biofortified foods in the context of rising global temperatures.