Instructional planning has increasingly been recognized as an essential element for good teaching at different levels of education. Instructional planning constitutes many things which teachers consider and do when they are planning for teaching. It provides a roadmap that assists the teachers to focus on achievable objectives and learners' needs, and to create a flow of events with starting, middle, and ending points in a lesson. As such, its primary purpose is to provide students with meaningful learning experiences. Although several studies have investigated instructional planning processes, studies of this nature have only focused on pre-service and in-service teachers. However, it is also of value to explore instructional planning practices of university graduate students in traditional mathematics and science degree programs, who are providing content knowledge and instructional support to K-12 teachers in schools through university-school partnership programs. The traditional mathematics and science degree programs are programs that prepare mathematicians and scientists, respectively. The graduate students in these programs have content backgrounds and career goals that differ greatly from K-12 mathematics and science pre-service and in-service teachers. There is also paucity of research that compares trained teachers' instructional planning practices with those of scientists and mathematicians in training who are involved in mathematics and science teaching in K-12 schools. Yet, such a knowledge base could be essential in designing outreach programs that would be successful in helping graduate students or scientists and mathematicians acquire desirable instructional planning practices. The assumption is that these graduate students or scientists and mathematicians would translate the desirable instructional planning practices into effective instructional practices in K-12 classrooms, and this in turn would improve the quality of mathematics and science learning among K-12 students. This study explores university mathematics and science graduate students' instructional planning practices for K-12 classrooms. All the participants were serving in a National Science Foundation (NSF)-funded GK-12 project. The GK-12 program is a mathematics and science education outreach program that uses the content knowledge and skills of graduate students and faculty at US universities to improve teaching and learning in schools. The acronym GK-12 is used to mean that the Fellows provide content knowledge and instructional support in classrooms from kindergarten to twelfth grade. (Contains 1 table.)