Dyslexia is a specific form of learning disability which comes along with diverse difficulties, both in learning, social and emotional fields. It obstructs the development of the individual at all levels of education. This research investigates students' spatial and geographical thinking and whether there is a differentiation of these abilities between dyslexic and non-dyslexic ones. For this purpose, 50 questionnaires were distributed to 25 dyslexic and 25 non-dyslexic students aged 14 using opportunity sampling from different areas (rural, urban). The questionnaire included spatial thinking exercises like mental rotation, plan views, shapes folding -- unfolding and mental manipulation of shapes and exercises by which geographical thinking is examined, according to the Greek geography curriculum. The results indicated that the non-dyslexic students had better performance than the dyslexic ones in all cases, except one, this of 2D--3D exercise. The most significant difference was in the section of plan views, mental rotation and folding - unfolding, whereas in the shapes mental manipulation, both children's groups faced difficulties. Although the research sample was limited, the results supported our hypothesis that non-dyslexic students would perform better on spatial and geographical thinking assessments.