Many states have begun the process of developing or adapting English Language Proficiency (ELP) standards to align with the Common Core State Standards (CCSS) and the forthcoming Next Generation Science Standards (NGSS). This need stems not only from a desire to ensure that "all" students receive the rigorous and systematic education they need to graduate from high school as college and career ready, but also because states must have ELP standards aligned to college and career readiness standards as a requirement to receive an Elementary and Secondary Education Act (ESEA) waiver. The Council of Chief State School Officers (CCSSO) has coordinated the development of a framework to assist states with this work. The goal of the English Language Proficiency Development (ELPD) Framework, hereafter referred to as the "Framework," is to provide guidance to states on how to use the expectations of the CCSS and NGSS as tools for the creation and evaluation of ELP standards. The CCSS as well as the NGSS spell out the sophisticated language competencies that students will need to perform across their respective academic subject areas. These include close reading and constructing effective arguments to support their conclusions, identifying a speaker's key points and elaborating on these ideas in group settings, and tasks such as constructing and testing models and predictions as well as strategically choosing and efficiently implementing procedures to solve problems. But they also implicitly demand students acquire ever-increasing command of language in order to acquire and perform the knowledge and skills articulated in the standards. English language learners (ELLs) thus face a double challenge: they must simultaneously learn how to acquire enough of a second language to participate in an academic setting while gaining an understanding of the knowledge and skills in multiple disciplines through that second language. As a result, state ELP standards corresponding to the CCSS and NGSS must be examined closely to determine what supports need to be put in place to provide ELLs with the help they need to access grade-level content while building their language proficiency. To that end, the Framework outlines the underlying English language practices found in the CCSS and the NGSS, communicates to ELL stakeholders the language that all ELLs must acquire in order to successfully engage the CCSS and NGSS, and specifies a procedure by which to evaluate the degree of alignment present between the Framework and ELP standards under consideration or adopted by states. A glossary is included. Individual sections contain figures, tables and references. (Contains 46 footnotes.) [This paper was developed with the English Language Proficiency Development Framework Committee in collaboration with the Understanding Language Initiative at Stanford University and World-Class Instructional Design and Assessment.]