A rapid and sensitive ultrahigh-pressure liquid chromatography tandem mass spectrometry (UHPLC–MS/MS) method was developed to simultaneously determine six plant growth regulators in bean sprouts with a simple preparation. Analyte extraction from samples was effectively performed using liquid–liquid extraction (LLE) by acetonitrile. Chromatographic separation was conducted on a C18 reversed-phase column with gradient elution. The analytes were detected by tandem quadrupole MS after negative electrospray ionization by multiple reaction monitoring. The developed method was validated by testing method specificity, matrix effect, sensitivity, linearity, accuracy, and precision.