This dataset contains stable carbon (δ¹³C) and oxygen (δ¹⁸O) isotope measurements of the planktonic foraminifera Neogloboquadrina atlantica dextral and Neogloboquadrina dutertrei from North Atlantic sediment cores spanning the Early Pleistocene. Measurements of N. atlantica dextral were obtained from IODP Sites 339-U1387, 306-U1313 and 306-U1312, and ODP Sites 108-659 and 172-1058 covering Marine Isotope Stages (MIS) 40 to 52 . Measurements of N. dutertrei were obtained from ODP Sites 108-659 and 172-1058 covering MIS 40 to 43, where both species co-occur. Stable isotope analyses were performed on groups of five specimens per sample at the Leibniz Laboratory for Radiometric Dating and Stable Isotope Research (Kiel University, Germany) using a Finnigan MAT 253 mass spectrometer coupled to a Kiel IV carbonate preparation device. Isotope values are reported relative to the Vienna Pee Dee Belemnite (VPDB) standard. The dataset provides species-specific isotope records from subtropical and transitional regions of the North Atlantic and allows comparison of the isotopic signatures of N. atlantica dextral and N. dutertrei in sites where both taxa are present.