This study investigates the effectiveness of Modified Multi-Component Cognitive Strategy Instruction (MMCSI) on expository text comprehension skills of students with mild intellectual disability (ID). Three students participated from inclusion classes of three different secondary schools in Turkey. The study was conducted using a multiple probe design across subjects. Expository text comprehension skills of the students were evaluated by using two different approaches: Reading Comprehension Test and Summary Writing. Comprehension scores of the summaries were assessed according to the following dependent variables: length of the summary, main idea scores, and quality. MMCSI was implemented in four phases: text structure instruction, modeling, guided practice, and independent practice. Study results showed that MMCSI was effective in a) improving the students' comprehension of descriptive texts, b) maintaining comprehension skills, and c) generalizing these skills to texts with different topic areas and structures.