Students completing Year 11 at Rainbow, or achieving equivalent qualifications elsewhere, may join Year 12 and take a course at 'A' level (Advanced Level). To be admitted to Year 12, students must have at least 5 C grades or above at IGCSE (or an equivalent course), including English and Mathematics. A good level of computer literacy is also required. Students with good results overall but without the necessary grades in English and/or Mathematics may enter Year 12 but will need to repeat these subjects in the November examination session.  

Year 12 students normally choose three subjects from Accounting, Art, Applied ICT, Biology, Business Studies, Chemistry, Economics, English Literature French, Geography, German, History, Mathematics, Music, Physics, Psychology, Sociology. Students take Cambridge AS level (Advanced Subsidiary) examinations at the end of Year 12 and if their results are satisfactory, they continue with these courses and take Cambridge 'A' levels at the end of Year 13.

Cambridge A Level exams are recognised internationally as entrance qualifications for university and our Career’s department supports and advises students through the difficult process of making university applications, as well as hosting an annual Career’s Fair that is attended by universities from the UK, the USA, Canada, Australia and may other countries. To boost their applications and improved their preparedness for university, Year 12 students are required to do two weeks of work experience after their AS exams and also have other opportunities to enrich their experience through such activities as the Model UN and involvement in CARE, our community service programme. We also guide students in applying for overseas scholarships and in 2010, our students were offered no less than 12 scholarships from universities around the world.