Assessment of individual behavioral characteristics (IBC) of domestic dogs is of both fundamental and practical interest to researchers. The paper presents the results of developing and assessing the reliability of a methodology for assessing IPC based on an online survey of owners who do not have special training. 4530 respondents took part in the survey. The questionnaire included 20 questions, which were rated on a Likert scale. Using the factor analysis method, 6 factors were identified, by which the IPC of different breed groups was compared according to the FCI classification, and the prognostic role of breed in determining differences in the IPC of dogs was assessed. A comparison of the data from our questionnaire with similar ones obtained in the USA and Japan (Q-BARK) showed that the identified factors generally coincided (Cronbach’s Alpha was 0.73, which indicates sufficient reliability of the methodology), although the questions for the Russian audience were formulated differently. Thus, this questionnaire can be used to assess the IPC, the formation of a modern behavioral portrait of a particular breed, its compliance with existing standards, as well as changes that occur as a result of the lack of selection, for example, for working qualities.