Contemporary research has reiterated the complexity of motivation as shaped by an array of personal and contextual elements. Drawing on a person-in-context relational view, the present study aims to explore learners' motivational constructions through their ongoing interaction with significant others such as teachers, peers, parents and extended family members in various social settings. Data from three Vietnamese high school students were obtained through interviews as social practice, observations, casual conversations, and visual materials. Findings reveal the scaffolding role of significant others in instilling the value of education, providing financial and language support, igniting and sustaining L2 motivation, and, rather negatively, exerting certain academic pressures. This study calls for more collaboration among significant others in providing ample opportunities for language learning and fostering learners' motivation.