NASA’s Science Mission Directorate (SMD) ties together diverse researchers, sponsors, and resources to develop the science community’s understanding of the universe. Within scientific organizations like NASA, it is important to establish clear strategies and goals to guide research and foster new discoveries across varying missions. SMD created a draft for their 2019 Science Plan, and a review of this draft is necessary to ensure that the plan establishes clear, attainable, relevant, and ambitious goals. Review of the Draft 2019 Science Mission Directorate Science Plan provides comments on and recommendations for SMD’s draft. Comments in this report focus on the level of ambition of the specified strategies in light of current and emerging opportunities to advance Earth and space science over the next 5 years, the ability of SMD to meet the science objectives in the most recent decadal surveys through implementation of specified strategies, additional strategies for SMD’s considerations, and the general readability and clarity of the draft. Recommendations in this report identify important improvements for the 2019 Science Plan.