Turbomachines are undoubtedly the key components of all power systems, and despite the impressive advances of the past century, there seems to still be room for improvement. While the reduction in the specific fuel consumption directly related to the components efficiency enhancement is the most natural and pursued objective, other aspects progressively acquire importance. Noise, life, reliability, and safety, to quote a few examples, require technological leaps that can only stem from solid, well-conceived, fundamental, and applied research. Those concerns are equally shared by the power generation world, the aerospace community, and the automotive one, all mainly focused on efficiency innovations.This Special Issue appearing in the International Journal of Turbomachinery, Propulsion, and Power [1] (www.mdpi.com/journal/ijtpp), collects original research articles addressing advances in computational and measurement techniques as applied to the above mentioned fields for the benefit of the academic and industrial research communities. These manuscripts originate from the 12th European Turbomachinery Conference (ETC12) held in Stockholm (Sweden) in March 2017 under the local coordination of the Swedish Royal Institute of Technology. The conference main objectives are the presentation of the latest developments in the turbomachinery field; the promotion of the transfer of this technology across Europe; and the creation of a forum suitable to disseminate and advertise the results of the research projects funded by the European Commission, as well the resultant benefits from the support by the Commission.The ETC series, started in 1995, is managed and organized by Euroturbo (www.euroturbo.eu), the European Turbomachinery Society, a not-for-profit international scientific organization legally established in February 2012, specifically organized to enhance the dissemination, exchange, and publication of top quality research in the field of turbomachinery. Yet, the policy of the society has always been to seek papers documenting good quality research rather than simply increasing their numbers, so that striving for quality rather than quantity has always been the society's motto.The research works appearing in this Special Issue were selected from a pool of two hundred full manuscripts submitted for review to the ETC12. They represent the outcome of a rigorous review process completed with the help of three independent referees supervised by a senior scientist, who rated them of journal quality.Six of the papers appearing in this issue are of computational nature, two deal with experimental work, one is of theoretical imprinting, and one is of the mixed experimental-computational type.