Foundation phase (grade R to 3) learners' underperformance against the curriculum is a growing concern in primary school. In South Africa, reports reveal a large number of learners underperforming in Reading and Mathematics. To understand this phenomenon, focus group discussions (FGDs) were held with 17 foundation phase teachers to probe their perspectives for qualitative data collection. Thematic results revealed many factors that could influence learners' underperformance. Social constructivism and development theories highlighted the importance of scaffolding learning. Education authorities should consider these factors in curriculum design and implementation to mitigate learners' underperformance in reading and Mathematics in primary schools.