Background: Qualea parvifloraand Qualea grandiflora (Vochysiaceae), commonly known in Brazil as "pau-terra" and "pau-terrinha," respectively, have been widely used in the treatment of ulcer and gastritis. These therapeutic effects are attributed to various compounds present in the plants, including phenolic compounds such as gallic acid, due to their important antioxidant activity. Objective: The aim of the present study was to validate a high performance liquid chromatography with diode array detection (HPLC-DAD) method for the quantitative determination of gallic acid in the stem bark of Q. parviflora and Q. grandiflorahydroalcoholic extracts. Materials and Methods: The chromatography analysis was successfully achieved on a Dionex column, Acclaim® 120 (250 mm × 4.60 mm, 5 µm) with a gradient elution of water and methanol at a flow rate of 0.8 mL/min and ultraviolet detection at 280 nm. Results: The validation data, including linearity, precision, specificity, accuracy and robustness of this method demonstrated good reliability and sensitivity. Conclusion: The method is able to quantify gallic acid in the stem bark of both species. What is more, the chromatographic peaks showed good resolution and there are also the advantages of easy sample preparation and a short time between each injection.