The research reported here examined factors that influence student tertiary level chemistry enrolment choices. Students enrolled in a first-year chemistry class were surveyed, using the Chemistry Attitudes and Experiences Questionnaire (CAEQ), three times throughout their academic year: at the start of the year (n=126), the end of the first semester (n=109), and the end of the second semester (n=84). Additionally, 19 students were interviewed using a semistructured interview protocol at the same stages throughout the year. A number of influences on student enrolment intentions are posited based on a modified version of Ajzen's Theory of Planned Behaviour: learning experiences, attitude-toward-chemistry and chemistry self-efficacy. The extent to which the students believe they had control over enrolling in chemistry and normative beliefs about enrolling in chemistry, also were investigated. Influential factors include chemistry self-efficacy (both positive and negative), prior secondary school experiences and the fact that chemistry is compulsory for some programs. Normative beliefs exert indirect effect with students having associates in a science related field more likely to enrol in second-year chemistry.