The purpose of the current study was to examine dimensionality and concurrent validity evidence of the EARLI numeracy measures (DiPerna, Morgan, & Lei, 2007), which were developed to assess key skills such as number identification, counting, and basic arithmetic. Two methods (NOHARM with approximate chi-square test and DIMTEST with DETECT classifications) were used to examine the dimensionality of each of the dichotomously scored measures. Both indicated unidimensionality for four of the EARLI measures (Counting Aloud, Counting Object, Measurement, and Pattern Recognition); however, results were discrepant for Numbers and Shapes. For the polytomously scored measure (Grouping), exploratory factor analysis indicated essential unidimensionality. In addition, the majority of the EARLI numeracy items did not appear to function differently by demographic variables, and scores from the EARLI numeracy measures demonstrated adequate concurrent relationships with scores from the WJ-III mathematics subtests.