Pengajian peringkat Menengah Rendah di SMK Tinggi Kluang terbahagi kepada 7 buah kelas; 4 kelas aliran perdana, dinamakan berdasarkan nama-nama lama SMK Tinggi Kluang, 1 kelas Rancangan Khas (KRK), 1 kelas Rancangan Khas Agama (KAA), 1 kelas Dual Language Programme (DLP) dan 1 kelas program pengkhususan sukan Olimpian (OLI). Setiap pelajar wajib mengambil 10 matapelajaran teras yang ditawarkan dan hanya kelas KAA mengambil matapelajaran tambahan iaitu Bahasa Arab. Untuk pelajar di kelas DLP, subjek Matematik dan Sains diajarkan di dalam dwibahasa, iaitu Bahasa Melayu dan Bahasa Inggeris.

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Lower Secondary studies at SMK Tinggi Kluang are divided into 7 classes; 4 mainstream classes, named after the old names of SMK Tinggi Kluang, 1 Special Plan class (KRK), 1 Special Religious Plan class (KAA), 1 Dual Language Program (DLP) class and 1 Olympian sports specialization program class (OLI) . Every student is required to take the 10 core subjects offered and only KAA class takes an additional subject which is Arabic. For students in DLP classes, Maths and Science subjects are taught bilingually, namely Malay and English.

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