Anacardium othonianum Rizz., popularly known as the Cerrado cashew tree, is widely used in medicine due to its therapeutic properties, including its antioxidant, anti-inflammatory, and antidiarrheal activities. Light is an important regulator of the growth, development of plants differentiation, and metabolism. Considering the influence of light on the production of phytochemicals, the aim of the present study was to evaluate production of gallic and 3,4-dihydroxybenzoic acids and amentoflavone in A. othonianum seedlings grown in vitro exposure to white, blue, green, red, and yellow light. The seedlings were evaluated with respect to the length of the aerial parts and the number of leaves, at 0, 20, and 40 days of treatment. The fresh and dry weights of the aerial parts and the levels of phenolic acid and biflavonoid were evaluated at 40 days via high-performance liquid chromatography with a diode array detector (HPLC-DAD). Regardless of the light wavelength used for the growth, the largest length of the aerial parts (5.54 cm) and an increase in the number of leaves (2.86-fold) were observed at 40 days. The largest accumulations of fresh weight (325.5 mg and 335.1 mg per seedling) and dry weight (83.3 mg and 84.5 mg per seedling) were observed in seedlings grown under red and yellow light, respectively. Relatively higher levels of gallic acid (0.66 mg.g -1 dry weight) and amentoflavone (1.41 mg.g -1 dry weight) were found in seedlings grown under blue light. In contrast, the 3,4-dihydroxybenzoic acid levels of the seedlings under red light increased (8.22 mg.g -1 dry weight).