Background: Maltol, as a type of phenolic compounds, is produced by the browning reaction during the high temperature treatment of ginseng. Thus, maltol can be used as a marker for the quality control of various ginseng products manufactured by high temperature treatment including red ginseng. For the quantification of maltol in Korean ginseng products, an effective high performance liquid chromatography diode array detector (HPLC DAD) method was developed. Materials and Methods: The HPLC DAD method for maltol quantification coupled with a liquid liquid extraction (LLE) method was developed and validated in terms of linearity, precision, and accuracy. An HPLC separation was performed on a C18 column. Results: The LLE methods and HPLC running conditions for maltol quantification were optimized. The calibration curve of the maltol exhibited good linearity (R2 = 1.00). The limit of detection value of maltol was 0.26 μg/mL, and the limit of quantification value was 0.79 μg/mL. The relative standard deviations (RSDs) of the data of the intra and inter day experiments were <1.27% and 0.61%, respectively. The results of the recovery test were 101.35–101.75% with an RSD value of 0.21–1.65%. The developed method was applied successfully to quantify the maltol in three ginseng products manufactured by different methods. Conclusion: The results of validation demonstrated that the proposed HPLC DAD method was useful for the quantification of maltol in various ginseng products.