Kathy O Sullivan is joint director of the Bachelor of Mathematics and Education (BME) undergraduate teaching programme in the University of Galway and lecturer for mathematics methodologies in the School of Education. Prior to commencing her role as a mathematics teacher educator in the University of Galway, Kathy worked as the National Programme Coordinator for the Professional Diploma in Mathematics for Teaching (PDMT) in EPI*STEM (The National Centre for STEM Education in Ireland). Kathy completed a postgraduate teaching qualificationin mathematics education in the University of Limerick and has experience in teaching mathematics to all levels in secondary school. Kathys PhD study investigated pre-service teachers knowledge of Numeracy and their ability to teach numeracy for disciplinary learning. Kathy developed the N framework to support teachers in planning for numeracy learning in the classroom. Kathy has a keen interest in teachers understanding of mathematical concepts and numeracy concepts in subjects other than mathematics. Kathy is passionate about encouraging numeracy across the curriculum as a whole school approach and enjoys supporting all teachers in embedding numeracy within their subject area.

Kathys research expertise are predominantly in the area of Numeracy and Mathematics Education. In recognition of her expertise, Kathy was invited to join the organising committee for the 16th International Congress on Mathematical Education (ICME 16) for the topic study group Mathematical Literacy, Numeracy and Competency in Mathematics Education which will take place in Prague in 2028. Dr O'Sullivan is a founding member of the International Community on Numeracy Education and hosted the inaugural International Symposium on Numeracy Edcuation at the University of Galway in 2025.

Kathy was invited to contribute an article titled Numeracy Across the Curriculum to the Oxford Research Encyclopedia of Education and a book chapter to the International Perspectives on Teaching and Learning for Mathematical Literacy, which features contributions from internationally recognised scholars.

Kathy sits on the Editorial Board of STEM Education (specialty section of Frontiers in Education) as a Review Editor and also am the lead Topic Editor for a special issue on Best Practices in Numeracy Education for the 21st Century. She regularly acts as a reviewer for journals such as Irish Educational Studies, Asian Journal for Mathematics Education, Educational Studies in Mathematics and Mathematics Education Research journal.

Dr O'Sullivan has also been invited to present her research at a range of national and international conferences, sharing insights into numeracy across the curriculum, teacher knowledge for numeracy, and innovations in mathematics education. Her contributions have helped shape conversations on effective practices and policy directions in both research and practitioner communities.

Kathy has a passion for teaching mathematics for understanding. She believes it is essential that teachers promote real life applications of mathematics as this will support students learning. In Kathys modules, she encourages pre-service teachers to become designers of their own resources and of the curriculum, and does this by providing them with the knowledge and tools to become pro-active teachers of mathematics.