Research in other countries found that environmental knowledge and environmental behavior are only weakly correlated. However, the correlations reported in master's theses in Taiwan were even lower, and many of them did not reach statistical significance. This paper reviewed 15 master's theses written in Taiwan in the last five years and discovered three typical problems in their measurement of environmental knowledge. These problems were: (a) overemphasis on factual knowledge; (b) lack of theoretical linkage between the knowledge assessed and behavior assessed; and (c) "correct answers" were too narrowly defined. These problems might have restricted the observed correlation between environmental knowledge and behavior. Based on this review, several principles to avoid these problems and recommendations for environmental knowledge education were proposed.