Penelitian eksperimen semu ini mencari tahu pengaruh penerapan scaffolding terhadap prestasi belajar dan keterlibatan siswa dalam pembelajaran tata bahasa. 1) Penerapan expert scaffolding (dengan metode ceramah) dan reciprocal scaffolding (dengan kartu pertanyaan dan pembelajaran kolaboratif) dengan 2) expert scaffolding (dengan metode ceramah) saja dibandingkan untuk dilihat perbedaan pengaruhnya. Penelitian ini melibatkan total 26 mahasiswa jurusan Sastra Inggris, Fakultas Ilmu Sosial dan Humaniora Universitas Buddhi Dharma, yang sedang mengikuti kelas Intermediate Grammar. Instrumen pengumpulan data yang digunakan adalah tes tata bahasa untuk mengukur prestasi belajar dan skala sikap untuk mengukur keterlibatan. Analisa data tes tata bahasa menunjukkan adanya peningkatan prestasi belajar pada kelompok eksperimen dan kontrol dan adanya perbedaan signifikan secara statistik antara rata-rata siswa sebelum dan sesudah perlakuan di kelompok eksperimen, tapi tidak pada kelompok kontrol. Analisa data skala sikap menunjukkan tidak adanya peningkatan keterlibatan dan tidak adanya perbedaan signifikan secara statistik antara rata-rata siswa sebelum dan sesudah perlakuan baik di kelompok eksperimen maupun di kelompok kontrol / This Quasi-experimental research investigated the effects of scaffolding on students’ academic achievements and engagements in learning grammar. Compared were 1) expert scaffolding (with lecturing) and reciprocal scaffolding (with question cards and collaborative learning) in the experimental group and 2) expert scaffolding (with lecturing) alone in the control group. This research involved a total of 26 students of English literature program, Faculty of Social Studies and Humanities of Universitas Buddhi Dharma, taking Intermediate Grammar. Administered as the data collecting instruments were a grammar test to measure academic achievement and an attitude scale to measure engagement. The data analyses with the grammar tests showed that there were improvements both in the experimental and the control group and that there was a statistically significant difference between the means of the students before and after the treatment in the experimental group, but not in the control group. The data analyses with the attitude scales showed that there were no improvements in engagement and that there was not any statistically significant difference between the means of the students before and after the learning took place both in the experimental group and the control group