Despite the fact that motivation is one of the most important individual differences (Dörnyei, 2005), there have been few attempts to examine what impact it has on studying English in Poland. This study aims to find out the general motivational properties of Polish students aged 15-16, focusing on the role of language learning goals, self-constructs, the influence of parents, peers and language learning anxiety. The second aim is to investigate which variables contribute significantly to students’ self-regulated behavior. To answer these questions, the researcher used a mixed methods approach, in which 236 students enrolled in compulsory education in southern Poland completed a motivational questionnaire and nine motivated learners participated in an interview. The quantitative data from the questionnaire was analysed using SPSS and the interviews were transcribed, coded and analysed qualitatively. The findings suggest that the students endorsed a number of language learning goals, such as knowledge orientation, international orientation and instrumental orientation. The role of parental encouragement, peer group pressure and language learning anxiety was limited. Although the questionnaire pointed to moderate levels of self-constructs, this was different for motivated learners who reported positive self-evaluations. Regression analysis showed that motivated behaviour, intrinsic motivation and the ideal L2 self influenced self-regulation.