Purpose: The purpose of this study was to evaluate the relative contribution of socioeconomic status (SES) on three grammatical measures--finite verb morphology composite (FVMC), percent grammatical utterances (PGU), and clausal density--in children between the ages of 4 and 9 years. Method: Data for this study were from the normative sample in the Edmonton Narrative Norms Instrument. For 359 children, hierarchical linear regression was performed to evaluate the amount of variance in FVMC, PGU, and clausal density that was uniquely explained by SES after accounting for child chronological age and language status (typical, impaired). Results: After child age and language status were controlled, SES was a significant predictor of PGU and clausal density scores, but not of FVMC scores. SES uniquely accounted for 0.5% of variance in PGU scores and 0.8% of variance in clausal density scores. Conclusions: Consistent with maturational accounts of children's development of tense markers, results of this study offer evidence that, among grammatical measures, FVMC is uniquely robust to variation in SES. Although significant, the variance of PGU and clausal density scores uniquely accounted for by SES was close to minimum. Clinicians can therefore include these three grammatical measures for assessing children of different socioeconomic backgrounds.