Probability literacy has gained importance in educational curricula. The aim of this research was to analyse secondary education teachers' attitudes towards probability and its teaching and to examine differences across the factors of gender, academic training, and work experience. From a positivist paradigm, a quantitative methodology was used. The sample consisted of 185 in-service teachers, and the instrument used was the Attitudes Towards Probability and Its Teaching questionnaire. The results suggested that gender had no effect on teachers' attitudes, but having a mathematics background was associated with a relevant weight on teachers' attitudes. Work experience presented a medium effect on the behavioural aspect of the teaching probability dimension, with better attitudes among teachers who had more work experience. This led us to acknowledge the importance of disciplinary knowledge in both initial and continuing training.