Tannins, especially condensed tannins (proanthocyanidins, PA), can strongly complex wheat gluten which alters gluten functionality. This work aimed to determine the effect of PA (extracted from sorghum, mean DP = 19.5) on strength and stability of gluten films and foams. Gluten films (with 0-10 mg PA / g gluten) were solution-cast and assessed for extensibility (TA.XT2 Texture Analyzer). Batter (with 0-25 mg PA / g flour) viscosity was assessed with Brookfield rheometer and Rapid ViscoAnalyser (RVA). In gluten film, PA (at 10 mg/g gluten) increased force to extend film by 2.1X, but interestingly, did not significantly decrease extensibility compared to the control, suggesting PA increased gluten film tensile strength. PA doubled batter viscosity compared to control, implying PA increased gluten polymer size, thus decreased mobility. This effect also increased batter stability: batters with PA (25 mg/g flour) exhibited 81% less volumetric liquid separation after 15 min floor time versus control. PA increased batter peak (53%) and final (35%) viscosity during an RVA cook-cool cycle. PA have elongated structures with sites for non-covalent interactions in close proximity, which likely enabled PA to interact with wheat gluten and starch. While glutenin-PA interactions are largely complete during the mixing phase, gliadin-PA interaction occur during cooking and have a significant impact on starch pasting. Low-quality wheat could be supplemented with PA to strengthen dough or increase batter viscosity, thus improving finished food quality. Beyond being a natural gluten strengthening agent, PA offers potential health benefits as a bioactive compound. Gluten-PA interactions could also be leveraged in biofilms for targeted delivery of bioactive compounds and nutrients and to modify food matrices to slow macronutrient digestibility profile, among others.