This paper reports a causal-comparative study of science anxiety among Form Four students in Penang. The Wynstra's (1991) Science Anxiety Inventory (SAI), which consists of six factors (i.e., danger anxiety, science test anxiety, math and problem-solving anxiety, squeamish anxiety, performance anxiety, and science classroom anxiety), was translated and modified to gauge the levels of science anxiety. Selected through a stratified random sampling, the sample comprises 160 students with equal number of males and females. Student ratings in Modified SAI were quantitatively analysed by gender using unpaired samples t-test with significance level set at probability level of 0.05. The findings indicate that Form Four females generally rated their overall science anxiety appreciably higher than did Form Four males. While there was no statistical significant difference between the ratings of males and females on science classroom anxiety, females rated appreciably higher than did males across five other subscales. These findings are discussed and implications for educational practice in the context of science learning in Malaysian classrooms are proffered. (Contains 2 tables.)