Assessment literacy remains a critical yet underdeveloped dimension of English First Additional Language (EFAL) teaching in many rural South African schools. This study explored how Grade 4 EFAL teachers in the Vhembe Cluster conceptualise and implement assessment practices within the constraints of multilingual and resource-constrained classrooms. Guided by Vygotsky’s Social Constructivist Theory, the study employed a qualitative case study design involving eight purposively selected Grade 4 EFAL teachers from four rural primary schools in Limpopo Province. Data were generated through semi-structured interviews, classroom observations, and document analysis and were analysed using Braun and Clarke’s reflexive thematic analysis. The findings revealed that assessment practices remain predominantly summative and compliance-driven despite policy emphasis on formative assessment. Teachers demonstrated fragmented understanding of formative assessment principles, while overcrowded classrooms, limited resources, and linguistic diversity constrained effective implementation. However, participants also displayed adaptive agency through culturally responsive practices such as storytelling, peer assessment, translanguaging, and low-tech digital feedback strategies. The study argues that meaningful assessment reform in rural South Africa requires more than policy compliance; it requires sustained professional development, contextualised mentoring, multilingual assessment approaches, and equitable digital support. The article contributes to emerging debates on decolonising assessment and strengthening teacher assessment literacy within African multilingual contexts.