Abbreviated and ultrafast breast MRI are emerging techniques that are now entering clinical practice and reflect an increasing understanding of breast cancer heterogeneity. These techniques may represent potential answers to shortcomings of mammographic screening, providing an opportunity to curb interval cancers, maximize diagnostic accuracy, and minimize overdiagnosis. Targeting more aggressive tumor subtypes may play a role in evidence-based de-escalation of breast cancer management, and abbreviated techniques have proved promising in early noninferiority studies. Functional characterization of tumors at MRI also has the potential for noninvasive tumor subtyping based on radiomics and radiogenomics and may ultimately streamline increasingly individualized breast cancer care. The purpose of this article is to describe techniques of abbreviated and ultrafast breast MRI, recognize their pros and cons, and discuss clinical applications and implications. The goals are to define terminology, consider diagnostic parameters, and emphasize key concepts. As these novel techniques enter clinical care and continue to evolve, it is essential that the radiologist understands the rationale and limitations behind these approaches and how and why interpretation may differ from that of conventional MRI. ©RSNA, 2020.