Petrophysics is the study of the physical (and chemical) properties of rocks and their interactions with fluids, and integrates downhole in situ data from logs with core and seismic data. This has significant applications in the hydrocarbon industry in terms of both exploration for, and production of, oil and gas. It is also an important component of the International Ocean Discovery Program (IODP) in helping to answer the many and varied questions posed by ocean research drilling expeditions around the world. This third Petrophysics Summer School will provide a unique workshop that will bring together experts from both academia and industry to give training in the theory and practice of petrophysics and, notably its applications across both IODP and industry. There are few opportunities for training, especially for non-industry researchers, and with recent reports indicating significant skills shortages in the hydrocarbon sector, the workshop could attract a variety of participants including those who might not normally engage with the IODP community. In addition, the summer school will strengthen links between IODP and industry, increase the visibility of IODP, provide essential training to the next generation of petrophysicists and, importantly, enable future expedition participants to best utilize these data in their investigations of the ocean floor. U.S.-affiliated students and researchers may apply for partial travel support through the U.S. Science Support Program. A limited number of travel grants are available. To apply for U.S. travel support, complete an online application by March 23, 2018.