Effective marine science teaching starts with well-written, measurable learning objectives that define outcomes for learners, inform instruction, and guide assessment. Yet, there are few resources to help marine science educators write effective learning objectives. To address this need, we created an evidence-based Marine Science Learning Objectives Tool (MS-LOT) to help marine educators evaluate their learning objectives. MS-LOT considers two critical aspects of learning objectives in marine science education: focus and assessment. As a case study, University of Georgia (UGA) Marine Extension and Georgia Sea Grant educators used MS-LOT to analyze their 207 learning objectives for 5th–12th grade educational programs. Findings revealed 1) gaps in content, science practices, and affective outcomes in instruction, 2) a focus on low-cognitive level outcomes, and 3) unmeasurable learning objectives. We respond to issues uncovered from the analysis and detail how MS-LOT will be useful for all marine educators, especially those working with K-12 learners.