In recent years, scholars have attempted to account for the silent reticence of Japan’s language learners based on a range of factors such as: deficits in L2 sociolinguistic proficiency (e.g. Korst, 1997); shyness (Doyon, 2000); problems with turn-taking behaviours (Sato, 1990); resistance to an oppressive system of education (Yoneyama, 1999); or washback from university entrance exams (e.g. Brown and Yamashita, 1995). This chapter contributes a new strand in the ongoing quest to understand more about these learners’ silent behaviour by exploring the intriguing connections between L2 classroom silence and the anxiety disorder of social phobia. While there has been much significant research on the debilitating effect that anxiety has on the academic performance of speakers of English as a second/foreign language (e.g. Aida, 1994; Horwitz, Horwitz & Cope, 1986; Mak, 2011; MacIntyre & Gardner, 1994; Woodrow, 2006), it seems strange that, to date, there appears to have been little or no attempt to explore the issue of L2 learner silence by drawing insights from the literature dealing with social phobia. Defined as a marked or persistent fear of specific social situations in which one is under the scrutiny of others (APA, 2000), social phobia differs from other anxiety disorders due to its emphasis on concerns regarding evaluation by others. These concerns are associated with heightened processing of the social self and a preoccupation with self-focused attention (McManus & Hirsch, 2007). Sufferers excessively self-monitor and focus on the impression they are making on others, fearing that their true self may be revealed at any moment. As these defining characteristics have a strong resonance to themes which emerged in my recent research on learner silence, this chapter examines how the findings of a large-scale, mixed methods investigation of L2 classroom silence within Japanese universities (King, 2013) relate to Clark and Wells’ (1995) cognitive model of social anxiety. Using data garnered from a series of semi-structured interviews, stimulated recalls and classroom observations, I discuss the self-focused attention, social fear beliefs and in-class safety behaviours of the Japanese learners of English who took part in the study and relate how these issues appear to significantly impact their L2 oral performance