Sustainable Development Goal 4 (SDG) has stressed the aspect of inclusive education. In Malaysia, the implementation of the Inclusive Education Program has been implemented, which is the placement of students with special educational needs (SEN) together with typical students in the classroom based on the experience of other countries. It is seen as more effective for SEN to obtain effective social interaction in life. To ensure that this inclusive education can be achieved, a universal learning design (UDL) has been developed. UDL is a framework for improving and optimizing teaching and learning for all individuals based on scientific insights into how humans learn. Therefore, the objective of this study is to identify the level of implementation of universal learning design (UDL) of mainstream teachers in the Inclusive Education Program (IEP) in primary schools in Kota Tinggi, Johor. The sample is a total of 82 mainstream teachers who teach the Inclusive Education Program at the primary school level. The census sampling method was used. The questionnaire that was constructed was adapted from the UDL Framework Scale 2023 and Borang Penskoran Evidens SKPM Gelombang 2 2016 with Cronbach's Alpha coefficient value a = 0.943 was used to collect data. Statistical Package for Social Sciences (SPSS) Version 29 software was applied to analyze the data obtained. Descriptive analysis found the level of implementation of the 3 principles of UDL in IEP by mainstream teachers at a high level.