The present research investigated the measurement invariance of two maximizing tendency scales; the Maximizing Scale (MS) and the Maximizing Tendency Scale (MTS), across three cultural and language multigroup comparisons. Archival data from 13 studies were analyzed (N = 6013) using a confirmatory factor analysis (CFA) and an item response theory (IRT) technique. CFA results indicate that both measures are noninvariant at the metric level. IRT results indicated that the MTS had six items that exhibited differential item functioning, but at the test level, expected score differences are small, so researchers may be able to safely use the MTS at the test-score level. Researchers should use caution when using the MS or MTS for cross-cultural or cross-national comparisons because observed group differences may be due to measurement non-equivalence.