The learning of Circle theorems is frequently highlighted as one challenging geometric content area for students at Senior High Schools (SHS). However, it remain unclear how students, especially girls are reasoning when dealing with problems in circle theorems. This descriptive study examined students’ ability and reasoning in solving problems involving Circle theorems. Two objectives were set to guide the study, focusing on SHS students’ levels of thinking in problem solving involving Circle theorems. A test, covering four basic theorems of geometry of circles in SHS curriculum, was designed and used to collect data from a purposive sample of 80 3rd-year students of Mfantsiman Girls’ SHS. The results showed that students’ thinking in Circle theorems follows the taxonomy of Uni-structural, Multi-structural, Relational and Extended abstract thinking levels. The study also found that about two-fifth of the students could not cope with problems involving relational and extended abstract reasoning, drawing of conclusions or even stating the four circle theorems. The study concludes that SHS mathematics teachers should reconsider how to teach deductively to improve the relational and abstract thinking levels of the 3rd-year students before they write the SHS final examinations. This could be facilitated through the use of SOLO taxonomy with super-item model as a diagnostic tool to ensure the growth of the students’ problem solving and reasoning skills in circle theorems.