Liquid chromatography (LC)-Orbitrap mass spectrometry (MS) and LC-time-of-flight (TOF) MS operating in full scan mode at a mass resolution of 140,000 (m/z 200) and 30,000 (m/z 556), respectively, were compared for quantification of pesticide residues in tea. Both methods were validated for 146 pesticides at spike levels of 0.1 and 0.01 mg/kg and compared in terms of recovery, intra- and inter-day precisions, selectivity, linearity, and matrix effect. The results of both analyses were comparable, and recovery and intra- and inter-day precisions were within the acceptable ranges for most pesticides. LC-Orbitrap MS was slightly superior to LC-TOF MS in terms of sensitivity and selectivity due to its higher resolution. However, even using high-resolution LC-Orbitrap MS with a narrow mass window of ±3 ppm, interference by coeluting matrix components was observed, indicating that full scan data are insufficient for unequivocal identification, and additional information such as fragment ions is necessary.