Differences between early and late Irish-immersion secondary school students are examined, not only in terms of academic outcome and target language ability, but also in terms of attitudes to learning the target language. Participants included a gender-balanced group of 97 students in Irish-immersion in fourth year of secondary school (mean age 15.5 years). The students were categorised as either early immersion (had attended an Irish-medium primary school) or late immersion students (Irish as core subject only until secondary). Participants completed a C-test and a Student Questionnaire based on Gardner's (1985) Attitude and Motivational Test Battery (AMTB), which looked in particular at their class anxiety, motivation and parental support for learning Irish. State examination results (Junior Certificate) were also collected and compared for the early and late immersion students. No difference was found between the groups in terms of overall academic attainment in Mathematics and Irish scores in Junior Certificate results. However the late immersion students performed significantly less well than early immersion student on more subtle tests of Irish ability and scored significantly higher on classroom anxiety. The discussion considers these outcomes and suggestions are made for provision of a transitional programme for late immersion students to address differences in their language proficiency and anxiety levels.