The total phenolic content (TFC), total flavonoid content (TFC), antioxidant activity, and polyphenol composition of extracts of rabbiteye blueberry fruit polyphenols (BBFPs), rabbiteye blueberry pomace polyphenols (BBPPs), and rabbiteye blueberry leaves polyphenols (BBLPs) were investigated. The highest TPC and TFC were found in the extract of BBLPs, followed by the extracts of BBPPs and BBFPs. The extract of BBLPs exhibited the highest antioxidant activity according to five antioxidant methods. All three samples exhibited significantly higher antioxidant activity than the positive control rutin. HPLC-DAD-MS(n) analysis showed that the extract of BBFPs contained nine different anthocyanins, while the extract of BBPPs contained only four of them. In addition, four caffeoylquinic acids, quercetin, and its three derivatives were detected in the extract of BBLPs. The results indicate that the fruits, pomace, and leaves of rabbiteye blueberry were good sources of polyphenols and natural antioxidants. These could be useful as a functional food ingredient beneficial to human health.