This paper investigated Virtual Learning and Undergraduate Students’ Academic Achievement in Mathematics during Covid-19 Lockdown in Ibadan, Oyo State. The study adopted One-group pretest-posttest Quasi-Experimental design. The population for this study was two hundred and eighty (280) First-year students in the faculty of Basic Medical and Applied Science, Lead City University, Ibadan, Nigeria. Sample for the study comprised Fifty (50) students who participated in the virtual learning in Applied Mathematics coded MTH 112 during COVID-19 Lockdown. The instrument for the study was Forty (40) objective questions optioned A to D on Applied Mathematics Achievement Test (AMAT). The instrument was validated and tested for reliability with reliability coefficients of 0.71. Student t-test statistics was used to test the Hypotheses generated at 0.05 level of significance. Hypothesis one revealed a significant difference in the achievement of students in Applied Mathematics when exposed to virtual learning, t-calculated (21.328) was greater than t-table (1.985). Hence hypothesis one was rejected. Hypothesis two also revealed a significant difference in the achievement of male and female students in Applied Mathematics in favour of male students, t-calculated (20.050) was higher than t-table (2.011). This infers that the male students achieved better than female students in AMAT when exposed to virtual learning. Hence, hypothesis two was also rejected. The study concluded that, Virtual learning encourages students’ achievement in Applied Mathematics and recommended virtual learning to be adopted especially where physical classroom is constrained.