Only quite recently has the concept of demotivation (as a partially neglected facet of motivationally-oriented investigations) come to the foreground of attention of researchers and educationalists interested in psycho-affective foundations of learning. Though literature on psycholinguistic underpinnings of learning is laden with varied probes into different pedagogical aspects of motivation, and thereby lack of it, studies directly attending to the notion of demotivation still suffer from a considerable paucity. Thus, faced with the above-said dearth of research on demotivating elements and their repercussions for didactics, the researchers in the current study set out for a partially full-fledged journey through the main underlying reasons for the learners' lack of motivation for learning English as a foreign language, particularly in the context of Iranian high schools. To come up with satisfactory answers to and justifications for the major research questions of the study, which tried to grapple with the demotivational bases of learning among Iranian EFL high school learners, a sample of 165 students from Maragheh (a city in East Azerbaijan, Iran) Nemouneh High School were selected as the participants of the study. The process of data collection was mainly carried out through the administration of a 50-item Likert scale demotivational questionnaire, which mostly centered around the learners' negative experiences of learning English as a foreign language. As a complementary phase to the current study, the English teachers instructing in the said high school were also involved in the course of data collection, through providing answers to an open-ended question concerning their experience of demotivating factors. Successive to the collection of data, several statistical procedures including one-way ANOVAs and chi-squares were run to analyze the learners' responses to the questionnaire items. The findings of the study, in brief, revealed no significant difference among the classes, except for the items related to the effect of teacher's personality and behavior, learners' experience of failure and learners' lack of success. The results also pointed to no significant differences among majors with the exception of the items attending to the effect of teacher's personality and behavior as well as the learners' experience of failure.