The COVID-19 pandemic forced educational institutions to shift from traditional face-to-face instruction to online learning, presenting unprecedented challenges for math teachers. This study aimed to explore the barriers that math teachers face when teaching math online. Using a quantitative approach, data were collected from 62 math teachers employed in a public school in a Midwestern state. The findings suggested that the main barriers to online math instruction include limited student engagement, technical issues, lack of face-to-face interaction, inadequate teacher training, and a lack of resources. These barriers have impacted teacher confidence and reduced the quality of math instruction. Teachers expressed a need for more professional development opportunities, technical support, and access to better resources to improve their online teaching skills. The findings of this study provided insights into the challenges faced by math teachers in online teaching and can inform the development of strategies and support to help overcome these barriers.