This study investigates the extent of identification and comprehension success achieved by Greek EFL high school students via lexical inferencing when encountering phrasal idioms while reading English as a foreign language. The results indicate that overall scores for L2 idiom identification and comprehension were remarkably low. Successful L2 idiom identification was found to correlate strongly but negatively both with frequency of occurrence of the component words of the idioms and with interlingual similarity while L2 idiom comprehension was found to correlate significantly positively with interlingual similarity only. No significant correlations were obtained between any of the four learner-related variables and the two main variables of L2 idiom identification and L2 idiom comprehension while guessing the meaning of unknown target idioms in text context. The findings of this empirical study lead to specific recommendations for L2 idiom pedagogy in the EFL classroom.