Abstract: Background and Objective: The adverse effects of drought can be mitigated by application of natural plant extracts as carrot root or antioxidants as β-carotene. Carrot root is characterized by high nutritional value and rich with bioactive constituents and antioxidants (phenolic compounds and carotenoids). This work aimed to compare between the physiological role of carrot root extract (5 and 10%) and β-carotene (25 and 50 mM) as seed soaking in inducing drought tolerance of sunflower plant (Giza 102 cultivar). Materials and Methods: Two pot experiments were conducted during two successive summer seasons (2015 and 2016) at wire house of National Research Centre, Egypt. The sterilized seeds were divided into three groups, the first group was soaked with distilled water, while second and third groups were soaked for 12 h with different concentrations of carrot root extract (5 and 10%) and β-carotene (25 and 50 mM). Results: Data showed that drought stress (50% FC) decreased quality and quantity of sunflower plants. Meanwhile carrot root extract and β-carotene mitigate the adverse effects of drought and induce plant tolerance through enhancement plant growth regulators; photosynthetic pigments; antioxidant enzymes; IAA; phenolic compound; osmolytes (TSS; proline, free amino acids); seed yield and seed composition as protein and oil content. Conclusion: Carrot root extract treatments were more pronounced than β-carotene treatments. Worthy, 10% carrot root extract was the most pronounced treatment in increasing drought tolerance of sunflower plant.