This dissertation aims to develop a risk management self-assessment model in third-party asset management institutions, according to a multi-criteria decision support approach and based on the guidelines of the ABNT NBR ISO 31000:2018 Standard. It seeks to demonstrate the model s applicability by developing an empirical study in an institution specialist in third-party resources management and investment fund administration. The methodology comprises: (i) literature review and documental analysis on the central themes of the research; (ii) definition of two analytical network structures, based on the clauses and items of referred Standard; (iii) use of the Analytic Network Process (ANP) method to assign weights to the items concerning the structure and the process of risk management, through consensual meetings involving specialists with experience in risk management; (iv) elaboration and application of the self-assessment instrument in the institution that manages third-party resources and administrates investment funds to assess their level of maturity in relation to the clauses and items of the ABNT NBR ISO 31000:2018 Standard, using fuzzy logic; (vi) application of the Importance-Performance Analysis (IPA) method to identify the items that should be prioritized, with a view to improving the institution s risk management. The main result is an innovative self-assessment system of institutions managing third-party resources that seek excellence in risk management to support decisions related to the continuous improvement of their risk management systems and processes. The empirical study in the organizational context of an institution specialist in third-party resources management demonstrated that it is plausible to determine the maturity level of this institution concerning the clauses and items of the ABNT NBR ISO 31000:2018 standard and to map the main challenges faced by this institution to realize value by the successful risk management.