Friendships and their different qualities have been shown to be important for adolescents’ socio-emotional development and psychological adjustment. In empirical research on such friendship qualities, the Network of Relationship Inventory—Relationship Quality Version (NRI-RQV) is a widely used questionnaire. Here, we conduct an extensive validation of a German version of the NRI-RQV, investigating its factor structure, reliability, and concurrent validity, in a sample of N = 679 adolescents aged 13–18 years. Applying multigroup confirmatory factor analysis, we further test whether the factor structure of the friendship quality construct holds across groups of males and females. Results showed that a structure with nine correlated first-order factors fit the data well, indicating nine distinct friendship qualities in males and females. Measurement invariance testing suggested the same underlying friendship quality construct, albeit differences in mean scores per gender. As evidence for concurrent validity, closeness and discordant friendship qualities showed expected correlations with empathy and social problems, respectively, but not with aggressive behavior. Overall, results indicate good psychometric properties for the German version of the NRI-RQV as a measure of friendship qualities in both males and females. (PsycInfo Database Record (c) 2020 APA, all rights reserved)