The aim of this study was to investigate mental health in Irish primary school teachers: depression, anxiety, stress and burnout in staff. One hundred and eighty-seven primary school teachers across the Republic of Ireland took part in a survey which comprised of a demographic questionnaire, the DASS21 and The Oldenburg Inventory Scale. Quantitative analysis was conducted on data collected using SPSS statistics software and non-parametric tests were run to assess relationships between variables as data was non-normally distributed. The conclusion drawn from the results demonstrated a statistically significant relationship between female primary school teachers and stress in comparison to their male counterparts. Results also indicated a statistically significant relationship between levels of stress and teaching pupils with Special Educational Needs. Finally, results suggested that there was a statistically significant relationship between years of service and disengagement.