This study was conducted in Sweden and aimed to give a deeper understanding of upper secondary English language teachers’ attitudes toward group work and how their attitudes can affect their implementation of group work in their EFL classrooms. Investigating teachers’ attitudes can provide insights into their experiences and opinions toward group work and how and why teachers use group work in their English classes. This study took a qualitative approach where semi-structured interviews were conducted with six upper secondary English language teachers from different areas in the country. The collected data was analyzed through the use of a thematic analysis method. The findings show that the teachers believe group work can be beneficial when it is used correctly and therefore contribute to language learning and practicing socializing, communicating, and discussing which makes students become more comfortable in the EFL classroom. The teachers also believe there are many challenges that come with implementing group work in their EFL classrooms which affects their use of it. Some of these challenges were language barrier, group composition, students' different language knowledge levels, assessment difficulties, and students' comfort level. The findings demonstrated that the teachers do not use group work frequently in their English classes mainly because of the many challenges they claim to deal with. In conclusion, the teachers believe there are both positive and negative aspects when using group work but the challenges the teachers face when using group work as a teaching strategy affects their implementation of it in their EFL classrooms.