The study examines the validity of four commonly used early numeracy curriculum-based measurement (EN-CBM) tools in relation to math criterion measures. Additionally, the investigation examines the reporting quality of the included studies as related to important features of assessing CBM's technical adequacy. For inclusion in the meta-analysis, research had to investigate and report on the criterion validity of EN-CBM--oral counting, numeral identification, quantity discrimination, missing number--administered to students in preschool, kindergarten, or Grade 1. Twenty-two studies published between 1997 and 2023 met inclusion criteria, with 272 correlations and 4,130 total participants. A meta-analysis with robust variance estimates for correlated and hierarchical effects was conducted to estimate the average weighted correlations between the four EN-CBM tasks and math outcome measures and to identify potential moderating variables (grade level, CBM type, criterion measure type, correlation lag time). Results indicated the average weighted correlation across all EN-CBM was significantly correlated with criterion measures (r = 0.48; 95% CI [0.430, 0.528]). The average weighted correlation between EN-CBM and criterion measures was significantly smaller for ENCBM oral counting and state test criterion. Results indicated that grade level and administration lag time did not significantly predict relations between EN-CBM and criterion measures. The quality coding results revealed many opportunities for improving information reporting across all indicators (attrition [M = 0.63], EN-CBM reliability [M = 1.48], scoring reliability [M = 1.24], and administrator training [M = 1.60]). Results are discussed in terms of implications for practitioners who administer EN-CBM in school settings.