Retrieval practice and spacing out studying help increase learning. Introductory Psychology students at nine colleges/universities took quizzes with more (RP+) or less (RP−) retrieval practice and more (SP+) or less (SP−) spacing between quizzes. We compared (N = 351) scores on class exams and on a standardized test. We also measured key student variables (e.g., depth of processing). GPA predicted a significant portion of variance in exam scores, R 2 = 0.05, F (1, 204) = 10.84, p = 0.001. We found a main effect for retrieval practice and a significant retrieval by spacing practice interaction, R 2 = 0.28, F (3, 201) = 27.38, p < 0.001. Students using SP+, as well as those with SP− and RP−, scored higher than students using SP− and RP+. In practice, closer attention needs to be paid to quiz and exam content overlap and the duration within which repetition is used.