Purpose: Reading and writing are foundational skills that provide access to educational, vocational, and social experiences. However, while the gap widens between the literacy skills of individuals with intellectual disability (ID) and those with typical development as they grow into adolescence, little is known about meeting the comprehensive literacy needs of adolescents with ID. This tutorial reimagines the assessment of literacy-specific skills for adolescents with ID as an individualized approach that will reveal a profile of strengths and challenges so they can receive targeted intervention. Method: Extant research investigating literacy achievement for individuals with ID is reviewed, followed by a discussion of emergent to conventional literacy skills and a conceptual framework within which to organize the skills. Then, an individualized assessment approach is presented that addresses considerations for the selection of complementary formal and informal measures and strategic analysis of the results. Results: A clinical case study depicting a literacy assessment of an adolescent diagnosed with ID is utilized to demonstrate the process for determining individual strengths and challenges in emergent and conventional literacy skills. Detailed discussion of assessment results and error analysis provide insight into her level of emergent and conventional reading and writing skills, which is then linked to intervention goal suggestions. Conclusion: Comprehensive individualized assessment batteries enable practitioners to align literacy interventions with each adolescent's needs in order to promote conventional reading and writing development.