A collaborative study was conducted to validate the suitability of an LC-MS/MS method for quantifying 128 residual veterinary drugs in six food matrices: honey, milk, egg, beef, pork liver, and lard. Twelve laboratories participated, including seven governmental, four commercial, and one incorporated foundation. Standard compounds, extraction powders, and matrices were provided to minimize material-related variations. Laboratories spiked samples with 5 ppb, 25 ppb, and 50 ppb levels, and reported recoveries along with chromatograms. At the 5 ppb spiking level, a significant number of compounds showed recoveries below 60% or above 125%, with the highest occurrence in milk (82 compounds), followed by honey (70), lard (68), pork liver (59), beef (54), and egg (49). However, at the 25 ppb level, the number of compounds with recoveries outside the range of 70%–120% significantly decreased, with pork liver showing the highest number (8 compounds), followed by honey (4), and only 2 compounds in other matrices. At the 50 ppb level, the numbers outside the range further decreased, with pork liver (5 compounds), beef (4), egg (4), lard (3), milk (1), and honey (1). These results indicate that the LC-MS/MS method performs optimally at a limit of quantification (LOQ) of 25 ppb, as the number of compounds with unacceptable recoveries significantly decreases at this level. By setting the LOQ at 25 ppb and filtering out poorly performing compounds, this method can be effectively optimized to serve as a reliable and robust approach for veterinary drug residue analysis in complex food matrices.