Abstract: This investigation monitored Achievement in activity-based biology instruction and the influence of learning styles in the Senior Secondary Schools in Lagos State, Nigeria. A quasi-experimental design was adopted. Two groups employed in the experiment were activity-based experimental group with intent class of 64 students and a control group with intact class of 72 students. A total of 136 students were exposed to treatment for six weeks using Instructional Package on Ecology (IPE), Learning Style Inventory VARK-B1 and Biology Activity-Based Achievement Test (BIAT). 2 by 4 factorial design and Analysis of Co-Variance were used to analyze the hypotheses on the data obtained while F-value and Multiple Classification Analysis (MCA) were applied to determine the source and magnitude of effects. There was significant main effect on treatment on biology (F2, 92) =15.40, p = .001 partial eta, Squared = .164. However, 89% (w2 = 0.887) of the total variance in Biology Achievement was accounted for by the two groups. No single learning style as moderator variable had significant influence in student achievements [F (3, 27) = 5.07, p = .006 partial eta, Squared = .36]. Only 20% (w2 = 0.20) of the total variance was accounted for by the four learning styles, Reading/Writing (M = 30.25, SD = 7.34), Aural (M = 24.38, SD = 5.15), Kinesthetic (M = 24.13, SD = 5.44) and Visual (M = 23.88, SD = 3.56). However, the learning styles altogether contributed significantly towards achievement in Activity-Based Biology Instruction. Multi-dimensional teaching that consciously accommodates various learning styles and from which learners intuitively selects their option of preferred learning is most suitable for each student. 

Key words: learning styles, activity-based, achievement, biology instruction, multi-sensory approach