The aim of the study was to validate the Russian-language version of the 25-item Hikikomori Questionnaire (HQ-25) recently developed by A. Teo and colleagues and successfully adapted in Japan and other countries. To test the reproducibility of the results, the psychometric properties of the Russian version of HQ-25 were analyzed on two different samples (N1 = 729, N2 = 451), recruited using an online survey in social networks in thematic groups associated with the hikikomori phenomenon, student communities of different universities. Confirmatory factor analysis showed satisfactory fit of the bifactor model with one common factor (severity of hikikomori symptoms) and 3 specific factors (socialization, isolation, emotional support) (for sample 1: (S-B)χ²(249) = 704.961; CFI = .928; TLI = .913; RMSEA = .050 (.046, .054), SRMR = .045; for sample 2: (S-B)χ²(249) = 561.636, CFI = .937, TLI = .925, RMSEA = .053 (.047, .059), SRMR = .045). Internal consistency, test-retest reliability were satisfactory. Convergent and divergent validity was confirmed (by correlating HQ-25 scores with the UCLA Loneliness Scale (version 3), Multidimensional Inventory of Loneliness Experience-3, Multidimensional Scale of Perceived Social Support, Marlowe–Crowne Social Desirability Scale). Obtained data confirm the criterion validity of the questionnaire. Similar results obtained on two different samples indicate the reproducibility of the study. The data of the psychometric analysis are supplemented by the content analysis of the interview, which explores hikikomori experiences in the Russian sociocultural context. Its results are in good agreement with the factorial structure of the questionnaire and can be useful for further development of theoretical views on the hikikomori phenomenon. The Russian version of HQ-25 can be used for research purposes to study and better understand individuals at risk for hikikomori.