Although many studies are available in terms of in-service teaching training programmes in the literature, studies on the motivation levels of in-service English teachers are quite scarce. This study aims to find out the effect of in-service teacher training programmes taken by Turkish EFL teachers and what factors influence their motivation under the effect of variables such as age, gender, the highest degree held by teachers, the subject of the highest degree, teaching experience, in-service training course forms, school degrees and school types where teachers work, in-service training course topics, countries where in-service training courses are held and ways of finding in-service training courses. 130 Turkish in-service EFL teachers taking their trainings both in Turkey and other countries took part in the study as participants. A new motivation scale was created and used by combining two different scales: an INSET course participation survey and a motivation to teach scale in the study. According to the results, public and female teachers are found more motivated compared to male and private school teachers. Furthermore, teachers complain about insufficient peer interaction, little trainer-participant communication, not being able to improve their English proficiencies and enlarge their networks and getting follow-up support. In addition, EFL teachers in Turkey prefer practical forms of in-service teacher training programs and topics closely related to ELT such as short courses, teaching practice, teaching young learners, teaching vocabulary and creativity more than other theoretical or time consuming forms. Finally, the research revealed that private school teachers are pleased with the quality of the courses they have taken so far whereas public teachers are more motivated to teach in terms of flexibility that their job provides them.