Laboratories serve as an integral part of geoscience education at most colleges and universities. While anecdotal evidence supports the beneficial impact of laboratories on science class learning, little quantitative research backs this statement. This study compared classroom data from students who completed a geoscience laboratory in conjunction with an introductory-level lecture-based course to those who completed the lecture course only. Laboratory-enrolled students performed better in the lecture class, resulting in an increase of 5.5% in their final class score. Even after controlling for GPA, laboratory enrollment accounted for a statistically significant proportion of the variance. Nontraditional students (age 25 and over) primarily benefited from the laboratory. Nontraditional students enrolled in lab performed 21.1% higher overall than their lecture course only nontraditional counterparts, and 4.9% higher overall than traditional students who enrolled in both the laboratory and lecture courses. Geoscience laboratories play a significant role in student learning and appear particularly important for nontraditional students.