We measured the concentrations of C37 alkenones in sediment samples from Ocean Drilling Program (ODP) Site 118-1165. From these concentrations, we calculated the unsaturation index of C37 alkenones (Uk'37) to quantify the evolution of sea surface temperatures in the polar Southern Ocean during the Miocene. To calculate temperatures, we applied the core-top calibration of Müller et al. (1998) for Uk'37. Alkenones were measured using a gas chromatograph with a flame ionization detector, Agilent Technologies, 7890/8890 equipped with an Agilent DB-1 column (60 m length, 0.32 mm diameter, 0.10 µm film thickness). C37 alkenone concentrations were quantified using internal standards of n-hexatricontane and n-heptatriacontane and were normalized to the dry mass of sediment extracted for each sample. Alkenones in some samples were measured using high performance liquid chromatography coupled with mass spectrometry (HPLC-MS) using a Zorbax Exclipes PAH column using the method of Liao et al. (2023). For samples measured using HPLC-MS, C37 alkenone concentrations were not quantified.