Integrating solar panels with crops in the same piece of land is possible using agrivoltaic (AV) systems. However, AV systems alter the microclimate and present several challenges to crop performance; therefore, site-specific crop development monitoring and yield assessment are crucial. In this context, a field experiment was conducted in 2024 to investigate the growth and crop performance of oat cultivated under a vertical AV system and open-field reference condition at Kärrbo Prästgård near Västerås, Sweden. The dataset presented in this article considers two different system designs, vertical AV and conventional ground-mounted photovoltaic (CGMPV) systems. The biophysical parameter leaf area index was used to monitor oat development throughout the growing season. At harvest, both quantitative and qualitative yield performance were assessed using kernel and straw yields, thousand-kernel weight, and kernel crude protein and fat content. All collected data were analysed using analysis of variance (ANOVA) with Tukey pairwise comparisons. It was observed that there was a significant variation in yield within the AV system. However, the mean total biomass (kernel and straw) in the AV system was higher than in both the reference and CGMPV systems; while the difference was not statistically significant compared to the reference system, it was significantly higher than that observed in the CGMPV system. Researchers can use this field-based data to better understand oat performance under the AV design and to perform further analyses or comparisons with yields from other locations, climatic zones, or system configurations. In addition, this empirical dataset can support the development and validation of crop models under similar conditions.