The present research examines the role of metalinguistic awareness (MLA) in positive transfer from a second to a third language. The main focus is on levels of metalinguistic reflection which emerged from the analysis of think-aloud protocols (TAPs). Previously, a reflexive dimension of MLA was established by means of the "Test d'habiletés métalinguistiques," which required participants to reflect on semantic and morphosyntactic aspects of their native language French. Introspective verbal data collected during a translation task revealed an applied dimension of MLA, which was shown to impact the extent to which unknown words in the target language German (L3) were successfully translated into the participants' native language French based on the positive influence of their second language English (L2). Besides the fact that this applied dimension of MLA was the strongest predictor of positive transfer, our observations point to the invaluable contribution of introspective data to complement findings based on language-inherent characteristics of crosslinguistic influence. [This paper was presented at the 13th International Conference of the Association for Language Awareness, Vienna, July 2016.]