This chapter provides an overview of research in computer-based writing instruction (CBWI). CBWI may entail any type of writing instruction with computers and may refer specifically to technologies that provide computer-generated feedback and instruction. The purpose of CBWI is to support students in improving their written products and writing processes, and to also optimize teacher labor regarding instruction and feedback. We argue in this chapter that the benefits afforded by CBWI are enhanced within the context of writing instruction that emphasizes principles of evidence-based writing practices and is situated within authentic writing communities. We conclude with a discussion about potential affordances and threats to writing instruction practices and communities from generative artificial intelligence tools. Future research directions for CBWI are discussed. [This chapter was published in: "Handbook of Writing Research (3rd Ed.)," Guilford, 2023.]