Objectives <p>This study sought to contribute to an ongoing debate over the dimensionality of the Self-Compassion Scales. Specifically, we aimed to (1) test the factorial structure of the Portuguese-language Self-Compassion Scale-Youth (SCS-Y); (2) evaluate whether total scores are sufficiently unidimensional to be interpretable; and (3) assess construct validity.</p> Method <p>The sample comprised 1467 Portuguese 8th graders (<i>M</i>_age = 14.1&#xa0;years, 48.8% girls). We tested the factorial structure of the SCS-Y using exploratory structural equation modeling&#xa0;(ESEM) and confirmatory factor analysis (CFA). The network alignment between self-compassion subcomponents was tested with exploratory graph analysis (EGA). Scale unidimensionality was evaluated using bifactor indices. Construct validity was evaluated by estimating correlations between SCS-Y scales and indicators of subjective well-being (SWB).</p> Results <p>A correlated six-factor CFA model and a two-bifactor CFA model fit the data well. Bifactor indices indicated that scores tapping into uncompassionate self-responding (i.e., self-criticism) were essentially unidimensional (ECV = 0.63, <i>ω</i>_<i>H</i> = 0.78). In contrast, there was greater multidimensionality in compassionate self-responding (i.e., self-compassion; ECV = 0.42, <i>ω</i>_<i>H</i> = 0.54), with the mindfulness and common humanity subscales explaining a sizeable amount of variance. The EGA revealed a two-dimensional structure (self-compassion and self-criticism communities). As evidence of construct validity, self-compassion was correlated with positive affect (<i>r</i> = 0.33) and self-criticism with negative affect (<i>r</i> = 0.43).</p> Conclusions <p>The Portuguese SCS-Y is a psychometrically adequate tool for assessing the six theorized subcomponents of self-compassion. While self-criticism is a well-defined unidimensional construct, caution is needed when interpreting a total score of compassionate self-responding.</p> Preregistration <p>This study was not preregistered.</p>