A rapid, sensitive and provident flow injection analysis (FIA) method was developed within the framework of a chemometric approach for the quantification of humic acid (HA) in the lignite obtained from Ilgın, Konya, Turkey. The proposed method allows automatic determination of 60 samples per hour over a wide calibration range (0–2000 mg L−1, R2: 0.9988) and needs only 10 μL of sample at a flow rate of mobile phase (X1), 2 mL min−1; pH of mobile phase (X2), 8, and system temperature (X3), 20 °C. The limits of detection (LOD) and quantification (LOQ) were calculated as 9.18 mg L−1 and 30.60 mg L−1, respectively, and the relative standard deviation (RSD) for 500 mg L−1 HA was calculated as 3.44 (n: 9). It was revealed that the standard deviation (SD) values of the proposed FIA method are lower than those of the spectrophotometric method.