Purpose: Our aim was to evaluate the psychometric properties of the online administered format of the Test of Narrative Language--Second Edition (TNL-2; Gillam & Pearson, 2017), given the importance of assessing children's narrative ability and considerable absence of psychometric studies of spoken language assessments administered online. Method: The TNL-2 was administered to 357 school-age children at risk for language and literacy difficulties as part of a randomized controlled trial, across three annual cohorts, at three time points (pretest, posttest, and 5-month follow-up). Cohort 3 students were tested using an online format at posttest and at follow-up. We compared the Cronbach's alpha internal consistency reliability of the TNL-2 online testing scores with in-person scores from TNL-2 normative data and Cohort 3 in-person testing at pretest, and interrater reliability for Cohort 3 across test points. In addition, we examined measurement invariance across test occasions and the criterion validity of the TNL-2, the latter based on its correlations with narrative sample measures (Mean Length of Utterance in words and the Monitoring Indicators of Scholarly Language rubric). Results: Internal consistency reliability, interrater reliability, and measurement invariance analyses of the online and in-person administration of the TNL-2 yielded similar outcomes. The criterion validity of the TNL-2 was found to be good. Conclusions: TNL-2 psychometric properties from online administration were generally in the "good" range and were not significantly different from in-person testing. When administered online using standardized procedures, the TNL-2 is valid and reliable for use in assessing narrative language proficiency in school-age children at risk for language and learning difficulties.