The study aimed to determine whether there was any significant difference in understanding levels between secondary school boys and girls on the concepts of environmental degradation, meteorology and climate change. Both structured survey and focus group discussions were used to collect information from 480 students, sampled randomly from 12 secondary schools in Morogoro region. The findings indicated that boys were significantly more knowledgeable than girls on the specified environmental concepts. This implies that girls lagged behind their counterparts in understanding important environmental concepts as specified in the school curriculum. Based on the findings of this study, it is recommended that girls should be inspired and encouraged to develop interest in natural science subjects which would enable them to broaden their understanding about environmental issues.