Marigold plant growth and orientation were improved by adding gibberellic acid (25, 50 and 100 mgL^-1) and β-sitosterol (20, 40 and 80 mgL^-1) as well as their interaction treatments. GA₃ (25 mgL^-1) was more effective on number of branches, fresh and dry weight of shoots and roots/plant. While, GA₃ (100 mgL^-1) significantly increased plant height. Leaf angle was more decreased with GA₃ than β-sitosterol application. Both GA₃ (100 mgL^-1) or β-sitosterol (40 mgL^-1) significantly induced flowering earliness and number of marigold plant inflorescences. While low concentration of both substances improved the other characters of inflorescences. GA₃ (100 mgL^-1) and β-sitosterol (40 mgL^-1) interaction significantly increased earliness, number and stalk length of marigold plant inflorescences. Pigments (Chl.a & b and  carotenoids) and biochemical constituents (total sugars, indoles and free amino acids) were significantly enhanced with GA₃ (25 mgL^-1) and / or β-sitosterol (20 or 40 mgL^-1) as foliar application. However, both the highest concentration of two bioregulators gave the highest phenolic content of marigold plant leaves. Additionally, GA₃ (25 mgL^-1) and β-sitosterol (40 mgL^-1) interaction was more effective on leaves biochemical contents (Chl.a, carotenoids, total sugars, indols and free amino acids). Phenolic content was permanent increased with the highest concentration of both growth substances. GA₃ and β-sitosterol appeared positive correlation between fresh weight of inflorescences and Chl.(a+b). All the results were significantly negative attributed with phenolic content of marigold plant leaves.