This article has 3 objectives that build on each other. First, we demonstrate how to obtain maximum likelihood estimates for dynamic factor models (the direct autoregressive factor score model) with arbitrary T and N by means of structural equation modeling (SEM) and compare the approach to existing methods. Second, we go beyond standard time series analysis (T large and N D 1) and conventional SEM (N large and T D 1 or small) by integrating both approaches. The resulting combined model offers a variety of new modeling options including a direct test of the ergodicity hypothesis, according to which the factorial structure of an individual observed at many time points is identical to the factorial structure of a group of individuals observed at a single point in time. Third, we illustrate the flexibility of SEM time series modeling by extending the approach to account for complex error structures. We end with a discussion of current limitations and future applications of SEM-based time series modeling for arbitrary T and N.Keywords: dynamic factor analysis, factorial invariance, maximum likelihood estimation, time series analysis Structural equation models have a long history in the social sciences and related disciplines and are well established in present-day research. Since their earliest use almost a century ago (Wright, 1920), structural equation modeling (SEM) has been extended in various ways, making it a powerful and highly general data analytic approach (cf. Muthén, 2002). The vast majority of research using SEM has focused on the variation among individuals. This applies equally to cross-sectional studies (e.g., confirmatory factor analysis) and longitudinal studies (e.g., latent growth curve models). A typical example of such a between-person structural equation model for N independent individuals with p D 2 orthogonal factors and q D 6 indicators, along with