The present study aimed at highlighting the possible effects of age, proficiency level, and the structural composition of Garden-Path (GP) sentences on EFL learners' comprehension. 80 Iranian EFL learners were recruited from the initial pool of 114 participants based on the results of an English proficiency test; 40 advanced, and 40 intermediate learners were selected. Moreover, two age-groups of teenagers and adults were specified based on the study's necessities. In order to determine the accuracy and also the time needed for comprehension of GP sentences, a software application was designed, which provided learners with a set of GP and non-GP sentences and depicted the elapsed time for each participant to show the correct understanding of the presented sentences on the screen. As statistical analyses revealed, the participants, apart from age and proficiency levels, had less difficulty in comprehending non-GP items. It was also concluded that different types of GP sentences imposed different degrees of difficulty for the participants to comprehend. Furthermore, "proficiency level," unlike "age," was found to be a determining factor for the comprehension of GP sentences for Iranian EFL learners.
