Writing to learn (WTL) is the act of making a subject or topic clear to oneself by reasoning through it in writing; it is a pedagogical approach that uses writing to facilitate learning (Zinsser 1988). Some researchers have reported favorable results associated with the approach (Balgopal and Wallace 2009; Bullock 2006; Hand, Hand, Gunel, and Ulu 2009). However, others have indicated that studies supporting WTL pedagogy tend to lack comparison groups, pre/posttest data, or the rich description that contributes to a rigorous qualitative study (Hübner, Nückles, and Renkl 2010; Kieft, Rijlaarsdam, and van den Bergh 2006; Klein 1999). Thus, existing research about WTL suggests that its effectiveness depends on context, leaving a need for further research to better understand the contexts in which WTL has a favorable impact on student achievement. In response to this need, we designed this mixed-method, quasi-experimental study to include pre/posttests and qualitative analysis of WTL journals. Writing to Learn WTL is based on the foundational idea that writing plays a role in the learning process. Zinsser (1988) explained how it is beneficial: … as a writer I [often] made clear to myself some subject I had previously known nothing about by just putting one sentence after anotherby reasoning my way in sequential steps to its meaning… often the act of writing even the simplest document clarified my half-formed ideas. Writing and thinking and learning were the same process. (p. ix) Given these benefits, it follows that teachers who adopt WTL as part of their pedagogy anticipate that writing promotes student learning. Engaging in the act of writing does not automatically enhance student learning, however; research suggests specific conditions need to be met in order for it to be effective. In a meta-analysis of 48 studies of WTL at the K-12 level, Bangert-Drowns, Hurley, and Wilkinson (2004) found that WTL can have a small to medium effect. They found the effect size increased with longer exposure to WTL experiences and when the writing task required metacognition. Further substantiating the latter finding, Hübner et al. (2010) found that WTL had a positive impact on learning when students were explicitly introduced to "specific cognitive and metacognitive strategies of self-regulated learning" (p. 18) and provided with an example of a WTL journal entry that illustrated those strategies. Kieft et al. (2006) found that WTL was more effective if the writing task matched with students' preferred writing approach. Thus, contextual factors influence WTL's impact on learning, the evidence supporting it is ambiguous, and while WTL has potential, it is not a cure-all (Bangert-Drowns et al. 2004; Newell, Koukis, and Boster 2006.).