The aim of this study is to examine the predictor and explanatory relationships among eighth-grade students’ affective factors of attitude toward geometry, geometry anxiety, and geometry self-efficacy, as well as the cognitive factor of spatial visualization skills, with geometry achievement. This relational survey study was conducted on 487 eighth-grade students during the 2012-2013 academic year. The tools used to collect data are the Attitude toward Geometry Scale, Geometry Anxiety Scale, and Geometry Achievement Test developed by the researchers; the Geometry Self-Efficacy Scale developed by Cantürk-Günhan and Ba?er; and the Spatial Visualization Test (adapted to Turkish by Y?ld?z). The researchers developed the model in consideration of the relevant literature. This model tests the direct and indirect relationships among the variables of affective factors, spatial visualization skills, and geometry achievement. The model’s fit indices were calculated and these fit indices show the model to have good fit (x² = 106.226; x² / df = 2.47; RMSEA = 0.05; CFI = 0.97; NFI = 0.95; NNFI = 0.96). Research reveals the relationship between spatial visualization skills and affective factors, between affective factors and geometry achievement, and between spatial visualization skills and geometry achievement to be positive and significant. Affective factors directly explain 26% of the variance in spatial visualization skills and 35% of the variance in geometry achievement, while indirectly explaining 7% of geometry achievement.