Investigations of both short-term natural climate variability, and long-term, large-scale changes in climate state are advanced by scientific ocean drilling at globally-distributed locations. Despite its global importance as both a contributor to climate change and a region that is most affected by global warming, the Arctic Ocean is the last major region on Earth where the long-term climate history remains poorly known. While many major advances in understanding were achieved in 2004 with the successful completion of IODP Expedition 302: Arctic Coring Expedition (ACEX), the record was hampered by generally poor recovery and by a 26-myr hiatus (or condensed interval depending on the age model) spanning the global transition from the Greenhouse to Icehouse climate states. In August-September 2022, IODP Expedition 377: Arctic Ocean Paleoceanography (ArcOP) will enable another step in reconstructing the detailed history of climate change in the Arctic over the last 50+ million years. The overall goal of the ArcOP drilling campaign is the recovery of a complete stratigraphic sedimentary record on the southern Lomonosov Ridge to meet the highest priority paleoceanographic objective: the continuous long-term Cenozoic climate history of the central Arctic Ocean. Key scientific themes to be addressed by ArcOP are represented in Figure 1. The expedition goals can be achieved through 1) careful site selection, 2) the use of appropriate drilling technology and ice management supported by two ice breakers, and 3) applying multi-proxy approaches to paleoceanographic, paleoclimatic, and age-model reconstructions. The expedition will complete one primary deep drill hole (LR-11B) to 900 meters below seafloor (mbsf; twice as deep as the ACEX core depth). This will be supplemented by a short drill site (LR-10B) to 50 mbsf, to recover an undisturbed Quaternary sedimentary section to ensure complete recovery for construction of a composite section spanning the full age range through the Cenozoic. Expected sedimentation rates two to four times higher than those of ACEX will permit higher-resolution studies of Arctic climate change. More information on ArcOP can be found at the expedition website: https://www.ecord.org/expedition377/.