Research with bilinguals apply different measures to assess proficiency, one of them being language background questionnaires, which include questions about individuals’ experience and self-rated proficiency. Studies suggest that bilinguals can report their proficiency consistently with objective measures (MARIAN et al., 2007; LUK et al., 2013; GERTKEN et al., 2014; BRANTMEIR et al., 2012). Within this context, the goal of the present study was to investigate the relationship between two distinct measures of proficiency. In order to do so, we correlated participants’ self-rated proficiency (N = 112) in the Language Experience and Proficiency Questionnaire (QuExPLi - Questionário de Experiência e Proficiência Linguística) with their scores on the TOEFL ITP. We also carried out a simple linear regression between the mean scores of the two measures. Results show a significant weak correlation between participants’ self-rated proficiency and their scores on the TOEFL ITP, as well as a significant regression equation. Also, when the scores on individual skills were correlated with participants’ self-rated proficiency on those skills (N = 16), significant moderate to strong correlations were found. These results add to research that have found that bilinguals are able to report their proficiency accurately; however, more studies in different contexts are needed.