The learning difficulties prevalent among mathematics students are widely documented. This case study explores the difficulties experienced by National Certificate (Vocational) Level 2 mathematics students at a Technical and Vocational Education and Training (TVET) College in Gauteng in the learning of functions. The primary research question was: What conceptual and procedural knowledge difficulties do NC(V) L2 students experience when learning the concept of functions in mathematics? Qualitative data was generated from the students (n=17) through lesson observations, test responses and interviews. The convenient sample of students all belonged to one L2 mathematics class. The findings revealed that the students experience conceptual knowledge difficulties in terms of defining a function, identifying functions, translating between representations of functions, and interpreting the behaviour of a function. The findings also revealed procedural knowledge difficulties prevalent among the students. The errors that students committed in this regard included factorisation errors, structural errors, misapplication and modification of the rules. In general, the findings indicated that the students in this sample lack procedural knowledge and conceptual understanding of functions. The lesson observations revealed a prevalence of several misconceptions regarding functions among the students which were seemingly not recognised nor remedied by the teacher. The teacher’s instructional practices thus appeared to be among the possible sources of the difficulties that the students experience in the learning of functions. This finding was also confirmed by the students during the interviews. Shaky foundations from previous grades were also a factor. / Dissertation (MEd)--University of Pretoria, 2020. / Science, Mathematics and Technology Education / MEd / Unrestricted