Global agriculture will face two major challenges in the future: population growth and climate change. One of the primary obstacles to agricultural productivity is environmental stress, with abiotic factors having a considerable negative effect on horticultural yields. As such, exploring effective strategies to mitigate plant stress is essential. Among these strategies, the use of biostimulants has emerged as an innovative and eco-friendly approach to boost growth and productivity in horticultural crops under stress conditions. Biostimulants, including seaweeds, fungi, bacteria, and amino acids, play a key role in alleviating stress effects. Their effectiveness is largely attributed to bioactive compounds such as polysaccharides, pigments, phenolics, proteins, phytohormones, and various micro- and macronutrients. Research indicates that these compounds can significantly reduce plant stress and enhance resilience. The effective use of bio-stimulants can reduce waste from fertilizers and minimize the risk of nutrient runoff that leads to environmental pollution. Economically, it enhances nutrient uptake, plant growth, and productivity under stress conditions, reduces input costs, and increases farmers' profitability. Therefore, the use of these compounds in greenhouse systems is not only environmentally significant but also economically important. This study delves into the application of biostimulants in horticulture under abiotic stress and highlights some of the key challenges associated with their broader adoption and implementation.