Computational thinking is a problem-solving process involving abstraction, algorithmic thinking, automation, debugging, decomposition, and generalisation. It has been increasingly regarded as an essential skill and many countries have attempted to include it in educational systems. In Indonesia, as well as including computational thinking as part of the Informatics subject, the government has encouraged its integration into various subjects, which requires teachers to have a clear and shared understanding of the concept. Thus, this study explores Indonesian mathematics teachers’ perceptions of computational thinking and its potential incorporation into teaching and learning mathematics. Semi-structured interviews were used to obtain rich insights. The findings reveal that mathematics teachers have oversimplified perspective on some components such as algorithmic thinking and automation, contributing to their vague perception of computational thinking as problem-solving, which may hinder the original purpose of integrating computational thinking into mathematics education. They also show that the teachers recognise their own importance for successful integration and that existing classroom practices and mathematics tasks can be used for integrating computational thinking into mathematics education. This study contributes to the literature on how teachers conceptualise computational thinking within mathematical domain, situated in the evolving educational context where the integration of computational thinking is still emerging. The study suggests that several factors related to teachers’ perceptions of computational thinking should be considered in professional development programmes to support its integration. These include focusing on encouraging teachers to select appropriate mathematics tasks that promote effective computational thinking integration and enhance their current teaching practices with computational thinking.