The COVID-19 pandemic has triggered significant changes in education systems worldwide. Until the lockdown in March 2020, teachers in Montenegro had solely conducted lectures in lecture theatres. Their previous use of online teaching aids was sporadic and was based on their assessments regarding the need to use them. During the pandemic, however, teachers were forced to switch to online lectures virtually overnight, thus turning the traditional model of education into a virtual model. This study explores Montqenegrin higher education teachers' perceptions of the challenges of implementing online teaching during the lockdown period. A total of 120 teaching staff from all faculties in four universities in Montenegro completed a questionnaire entitled: 'Challenges and opportunities of online teaching in Montenegro'. The analytical findings revealed that all teachers experienced challenges when providing online lectures.