<p>Organic solar cells (OSCs) are promising clean-energy technologies, yet their performance is still constrained by interfacial energy losses and charge recombination. Engineering efficient interfacial layers that regulate exciton dissociation and charge transport are therefore essential for further improving device performance. Ti₃C₂T_x MXene combines metallic conductivity, tunable surface chemistry, and strong light–matter interactions, offering a promising interfacial platform for organic optoelectronic devices. These properties hold great promise for forming efficient interfacial charge transport pathways with organic semiconductors, thereby enhancing exciton dissociation efficiency and suppressing interfacial charge recombination, ultimately improving the power conversion efficiency of OSCs. Here, we investigate a series of ultrafast physical processes at the interface between Ti₃C₂T_x MXene and the conjugated polymer poly(3-hexylthiophene-2,5-diyl) (P3HT), including plasmon-induced phonon thermal effects, exciton dissociation, and charge transfer following photoexcitation. Bilayer films comprising either P3HT or P3HT: [6,6]-phenyl-C₆₁-butyric acid methyl ester (PC₆₁BM) were combined with Ti₃C₂T_x MXene using a floating-film method. Ultrafast transient absorption spectroscopy reveals that exciton‑dominated energy transfer at the MXene/P3HT interface accelerates the ground‑state bleaching (GSB) recovery of P3HT. In contrast, at the MXene/P3HT:PC₆₁BM interface, charge transfer predominates, leading to a slower GSB recovery. These findings provide mechanistic insight into ultrafast exciton relaxation and charge-transfer processes at MXene/organic semiconductor interfaces, suggesting the potential of Ti₃C₂T_x MXene as an interfacial layer for organic optoelectronic devices.</p>