The use of concurrent data elicitation procedures (e.g. think-alouds, eye-tracking, response time) to investigate learners' cognitive processing and processes is becoming more prominent in research designs as researchers seek to acquire a better understanding of how second language (L2) learners process L2 data (e.g. Martin et al., 2019; Rogers, 2019; Thinglum, 2019; for more recent studies employing concurrent procedures, see Leow, 2019). At the same time, an increasing number of studies have empirically investigated the reactivity of think-aloud protocols in second language acquisition (e.g. Medina, 2019; Morgan-Short et al., 2012). While the studies that have addressed the reactivity issue have yielded mixed findings, only a few studies (e.g. Adrada-Rafael & Filgueras-Gómez, 2019; Sachs & Polio, 2007) have addressed the written mode, particularly in the context of L2 writing that incorporates feedback. As part of a larger study of written corrective feedback, the present study investigates the possible reactive effects of think-alouds during exposure to written corrective feedback, which was provided on learners' L2 writing, on their L2 development. Fifty-nine Korean university learners of English as a foreign language, randomly assigned to either a think-aloud or to a non-think-aloud (silent control) condition, participated in the study. L2 development was measured by a written story-retelling task and a multiple-choice receptive test. Results showed that thinking aloud while processing written corrective feedback during three feedback sessions did not affect learners' development of receptive knowledge and their ability to produce the target structure in a new piece of writing when compared to a non-think-aloud condition.