The development of strong writing skills is a critical (and somewhat obvious) goal within the classroom. Individuals across the world are now expected to reach a high level of writing proficiency to achieve success in both academic settings and the workplace (Geiser & Studley, 2001; Powell, 2009; Sharp, 2007). Unfortunately, strong writing skills are difficult to develop, as they require individuals to coordinate a number of cognitive skills and knowledge sources through the process of setting goals, solving problems, and strategically managing their memory resources (Flower & Hayes, 1980; Hayes, 1996). Given the difficulty of this process, students frequently underachieve on national assessments of writing proficiency (National Assessment of Educational Progress, 2007, 2011). The successful acquisition of this complex set of skills largely depends on the instruction and feedback provided to students as they develop. Previous research suggests that writing proficiency is best enhanced through strategy instruction (Graham & Perin, 2007), along with extended practice and individualized feedback (Kellogg & Raulerson, 2007). Importantly, curricula aimed to meet these goals can be extremely difficult to implement. This method of writing instruction demands a significant amount of time from teachers, ranging from the time required to prepare materials and instructional content to the process of reading, editing, and providing individualized feedback on students' essays. Unfortunately, teachers rarely have enough time to devote to this process, as they are faced with increasingly large class sizes and, as a consequence, have reduced time for classroom instruction and planning (The National Commission on Writing, 2004). In response to these issues surrounding effective writing pedagogy, there has been an increased effort to develop computer-based systems for writing assessment and instruction (Shermis & Burstein, 2003, 2013). These systems vary widely in their primary purposes, from the automated scoring of student essays to the provision of formative feedback or the explicit instruction of writing knowledge and strategies (Dikli, 2006; Graesser & McNamara, 2012; Roscoe, Allen, Weston, Crossley, & McNamara, 2014; Weigle, 2013; Xi, 2010). Despite the importance of writing strategy instruction and feedback, the majority of research conducted on this topic has focused on the development of computer-based systems that can provide reliable and valid scores to students' essays. However, more recently, researchers have placed a stronger emphasis on the development of computer-based systems that incorporate more instructional materials, such as formative feedback and explicit instruction on the writing process (Roscoe et al., 2011). In this chapter, we provide an overview of computer-based tools and techniques that are currently being used to support writing instruction and practice. Additionally, we discuss more recent advances in this field with suggestions for future research and development. [This chapter was published in: "Handbook for Writing Research 2016," p316-329.]