IntroductionMotivation is a driving force behind man’s behavior which has led to many psychological studies throughout the world. Moreover, it is the fuel for successful learning. While intrinsic motives provide the internal rewards, extrinsic motivation supplies the required external rewards to keep the engine of learning running. Knowing the factors which impact intrinsic/extrinsic motivation helps educators target their efforts at a higher level and make more informed decisions.MethodThis study intends to examine how intrinsic vs. extrinsic motivation may be influenced by demographics including learners’ background factors of major, age, and occupation and to determine the relationships that may exist between intrinsic and extrinsic motivation. To this end, an explanatory sequential mixed-methods research was conducted at one of the public universities in Shiraz on the majors of Elementary Education, Educational Affairs, Social Studies and Theology, and the Arabic language which were selected through cluster sampling. These students were having their English courses at the university. Based on Krejcie and Morgan’s formula for sample size, a questionnaire was administered to 100 participants to collect quantitative data. Moreover, semi-structured interview sessions were conducted with one fourth of the participants.ResultsUsing Multiple Analysis of Variance (MANOVA) and Pearson correlation, we found that learners’ background factors of age, field of study and professional status did not affect intrinsic nor extrinsic motivation. However, significant and positive relationships were found between intrinsic motivation and total motivation index, and between extrinsic motivation and total motivation index. Qualitative data obtained from the interviews were analyzed using a thematic analysis. The results of the interviews showed some new illuminating trends as revealed from the participants’ responses and it was found that most interviewees followed intrinsic motives and considered motivation as a factor of great significance.ConclusionIn the English as a Foreign Language (EFL) context in which our study was conducted, instructors can follow more similar classroom motivational techniques and strategies since neither type of motivation was influenced by the variables of different major, age and occupation. Though many studies have shown that EFL learners are more extrinsically motivated in comparison with ESL ones, our study revealed that participants were more intrinsically motivated. Thus, this study may be replicated in other educational contexts such as an ESL context. The study can also be repeated in some universities in which other educational systems such as coed education is used to see the possible similarities and differences. Motivation is the important stimulant to impel the learners to achieve their learning goals; thus, it should receive sufficient attention in various educational settings.