A number of studies have reported differences in sense of mastery and perceived control across different subgroups. Yet, few have examined measurement invariance, an important prerequisite for valid comparisons. This study examines the factorial structure and measurement invariance of the perceived constraints (PC) facet of Pearlin and Schooler’s (1981) Sense of Mastery Scale (SM) which is a commonly used short form of the widely used SM scale. Confirmatory factor analyses using AMOS and Mplus were conducted to explore dimensionality and test for measurement invariance in factor structure, factor loadings, intercepts, and residual variances across gender, age, education, income, and employment status in a large (N = 19,858), nationally representative sample of Norwegian males and females aged 16–100. The data supported a modified unidimensional model specifying correlations between the error terms of items 4 and 5, or possibly two highly correlated dimensions (r = 0.90). Metric invariance of the scale was shown for age, education, and employment, whereas invariance at the strong and strict levels was shown for gender and income. Partial invariance at the strong level was shown for age. This Norwegian study supported a modified unidimensional structure for the abbreviated SM scale. Invariance testing indicated that comparisons across genders and income levels are unproblematic, whilst comparing mean scores across education and employment status is not justified. Latent, but not sum score means are comparable across age. Future studies using all 7 items of SM scale should provide more information on dimensionality and measurement invariance.