This cross-institutional study investigated the student-centred, home, school and society related causes of absenteeism among 1000 undergraduate students from two public universities, 500 each from The University of the West Indies, (UWI), Cave Hill Campus, Barbados and The University of Ibadan (UI), Oyo State, Nigeria. Results revealed that the students were absent from lectures for student-centred, home, school and society related reasons and there were significant differences between UWI and UI students' reasons with school causes being the key factors for absenteeism among the students from both institutions. Additionally, gender differences were found among the Nigerian undergraduates' student-centred and school causes of absenteeism while gender did not affect the causes of absenteeism among the undergraduates in Barbados. These results were discussed with the hope of understanding and tackling absenteeism among the students from the two different institutions.