Across many countries, young people are differentiated into academic and vocational tracks, a pattern that is closely related to their social class background. The Irish secondary system has been largely undifferentiated, but the introduction of a pre-vocational programme, the Leaving Certificate Applied (LCA), has brought an element of tracking into upper secondary education. This article explores whether allocation into the LCA track reflects processes similar to those highlighted in international research. It goes further than these studies by explicitly recognising the role of school organisation in influencing student's learning careers and educational decisions. The purpose of this paper is to estimate the determinants of track placement in the Republic of Ireland. Using in-depth qualitative case study interviews with students from Irish post-primary schools, this paper examines the factors influencing students' decisions to enter the LCA programme. This paper explores the extent to which individual agency and school-level factors influence track choice by focusing on the learning careers of individual students within specific school contexts.