The objective of this study is to better understand the process by which K-12 school districts select curricula materials in four critical subject areas: Mathematics, English Language Arts, Science, and History and Social Studies. This research has two primary goals: (1) to understand the process by which K-12 school districts select and adopt full-course curricula materials; and (2) to understand the degree to which K-12 school districts are aware of and adopted Open Education Resources (OER). Key findings of the study were: (1) Over three-quarters of districts have made a full-course curricula decision in the past three years, with two-thirds of these making decisions in more than one subject area. The most common subject area is Mathematics, followed by English Language Arts; (2) Adopting a full-course curriculum is a group activity. Teachers almost always play a role, typically joined by administrators and principals. Parents and outside experts are included by about half of the districts; (3) There is no single factor that drives a district selection process, with most districts citing five or more factors as "very important" or "critical" to their decision. Comprehensive content, working with current technology, are cited most often; (4) Districts select full-course curricula materials from over two-dozen publishers. Three of these, McGraw-Hill, Pearson Education, and Houghton Mifflin, are cited most often; (5) The vast majority of district adoption decisions are driven by an external factor: changing standards. Districts typically initially consider 3 to 5 alternatives, narrowing that number to 2 or 3 for a final decision. Most decision processes take the better part of a year to complete. The curricula materials being replaced are usually 6 to 10 years old; (6) Awareness of copyright and the public domain is much higher among districts than is awareness of Creative Commons licensing. Nearly three-quarters of respondents claim some level of awareness of OER, but this drops to only one-third when awareness of licensing is included; and (7) K-12 school districts have a greater degree of awareness of OER materials than of OER concepts and definitions. Two-thirds of all districts are aware of at least one OER full-course curriculum, with 37% having actively considered at least one for adoption. A full 16% of districts have adopted at least one full-course OER curriculum.