Online Learning in Educational Research Volume 3, Issue 1, 1-13. e_ISSN: 2798-2351 https://www.journal.foundae.com/index.php/oler/index DOI: 10.58524/oler.v3i1.211 Effectiveness of Online Mathematics Learning during Covid-19: Empirical Evidence from a Tertiary Institution in Ghana Loretta Arhin-Larbi * Christopher Owu-Annan Department of Mathematics Education, University of Education, Winneba, GHANA Department of Mathematics Education, University of Education, Winneba, GHANA Article Info Abstract Article history: Received: March 27, 2023 Revised: May 8, 2023 Accepted: June 12, 2023 This study investigated undergraduate mathematics students' perception of the effectiveness of strategies employed in learning mathematics online in the Covid- 19 era. The study was grounded in a pragmatic paradigm, using a sequential explanatory design with questionnaires and interview guides as the research instruments. A simple random sampling technique was used to select three hundred and seventy-nine (379) third-year undergraduate mathematics students within the central region of Ghana. The quantitative data were analyzed using descriptive statistics such as frequencies, percentages, means, standard deviation, and percentages, whiles the qualitative data were analyzed using content analysis. The findings of the study revealed that the combination of video, audio, and text-based materials in the online mathematics lessons was the most effective online instructional delivery strategy that the students perceived, whiles limited interaction between lecturers and students in online lessons was rated as the least effective in supporting their online learning. Also, access to the Internet for online lessons was the topmost challenge to online learning of mathematics experienced by undergraduate mathematics education students during the Covid-19 era. The study concludes that undergraduate mathematics students' perceptions of the effectiveness of online instructional delivery strategies are key for successful online mathematics learning; hence educators and institutions should ensure its success. The study recommends that Mathematics lecturers be trained continuously on effective strategies for online instructional delivery. Additionally, the telecommunication industry should improve network connectivity in the country, and universities should make their online learning platforms accessible without data to mitigate students' challenges with internet data. Keywords: Instructional delivery; Online learning; Online learning challenges; Undergraduate. To cite this article: Arhin-Larbi, L., & Owu-Annan, C. (2023). Effectiveness of online mathematics learning during covid- 19 era: Empirical evidence from a tertiary institution in Ghana. Online Learning in Educational Research, 3(1),1-13 INTRODUCTION The onset of Covid-19 saw rapid growth in online learning worldwide since it became the main avenue for continuous teaching and learning amid the pandemic. The shift to online learning by most educational institutions has necessitated more research to be conducted in this area. The global pandemic of Covid-19 has also prompted an extraordinary response in education to investigate the practical and pedagogical issues of meeting students' learning requirements during difficult times. Online learning comes with challenges, such as students feeling isolated, a lack of technical equipment such as computers and tablets for studies, and technical issues involving software usage * Corresponding author: Loretta Arhin-Larbi, Department of Mathematics Education, University of Education, Winneba, Ghana.  loretta1050@gmail.com