The goal of the present study was to identify the multidimensional factor structure of external barriers to substance abuse treatment and test its invariance across gender, ethnic, and age groups in a sample of 518 substance abusers assessed at a centralized intake unit. Exploratory (EFA) and confirmatory factor analyses (CFA) demonstrated a well-defined multidimensional factor structure of highly differentiated external barrier factors: time conflict, treatment accessibility, treatment entry difficulty, and financial problems. Furthermore, multi-group CFA tests were used to test equivalencies of the measurement and structural models. The statistical fit results supported the invariance of the ethnic groups. Although there were some gender and age differences in measurement and structural relations among the external barrier facets, the model fit indices results provided support for the invariance of both measurement and structural models. The findings suggest that it would be reasonable to consider the pattern of factor loadings and structure relations as invariant across gender, ethnic, and age groups.