Abstract Introduction Studies based on knowledge, attitude, and practice (KAP) theory are conducted to identify ways to improve strategies aimed at preventing and combatting certain conditions or diseases, to understand the way how behavioral changes are assimilated by the populations, and to reorient interventions. In view of the coronavirus disease 2019 (COVID-19) pandemic, studies based on KAP theory have been useful to better understand certain behaviors, such as adherence to prevention measures and control of the spread of the virus. Objective To describe the process of cross-cultural adaptation of two complementary instruments for assessing KAP regarding the COVID-19 pandemic in the Brazilian population. Methods Two independent translators proposed a first Brazilian Portuguese version of the scales. The cultural adaptation and pre-test of the Brazilian Portuguese versions occurred at different stages, using a panel of specialists and a subsample of the target population, respectively. Results The pre-test of the adapted instruments involved 30 Brazilian adults (mean age = 41.8 years; standard deviation = 4.24) and was carried out to assess instrument understanding and applicability. The participants informed they did not have difficulties to self-complete the instruments and reported a high level of clarity and understanding. Conclusion Both instruments can bring an opportunity to study behavioral constructs about COVID-19 in the Brazilian population, aiming to articulate strategies that enable the fulfillment of effective preventive measures.