Unwillingness to communicate (UWTC) was initially conceptualized as a trait-like predisposition in L1 studies, but later research shifted the focus to willingness to communicate (WTC). In second language acquisition, WTC was introduced as a situational construct where time is highlighted by the immediate context of decision to communicate. However, some previous studies on UWTC have pointed to enduring cultural factors shaping decisions in the immediate context. Using Vygotskian sociocultural theory, this study proposes heterochronic mediation as the means through which factors in the sociohistorical timescale influence situated decisions of UWTC in experiential time. It considers 12 high-school learners of English in a rural area in the Republic of Yemen using classroom observations, interviews, and journals collected over one semester in 2015. Coding of UWTC actions and stated influences was both deductive and inductive. Actions and statements were compared with field notes and analyzed for possible social origins. Findings of the study revealed that lower level timescales alone did not completely constitute UWTC, but were influenced by social, cultural, and historical factors. Higher level timescales did not directly constrain student UWTC, but indirectly through individual interpretations. Research and pedagogical implications are given.