In 2012, the Maine legislature passed a bill requiring public school districts to implement proficiency-based high school diploma requirements. Amendments were passed in subsequent years, and several additional bills related to this policy were introduced in the most recent 128th Legislative Session in early 2018. These bills were considered by the Joint Standing Committee on Education and Cultural Affairs, but have not yet had final action by the full Maine legislature at the time of this report's publication. Beginning in 2012, the Maine Legislature's Joint Standing Committee on Education and Cultural Affairs has annually requested that the Maine Education Policy Research Institute (MEPRI) conduct empirical research studies designed to compile data, examine progress and explore impacts regarding implementation of this state policy within school districts across the state. In 2017-2018, Phase VI of this ongoing research included two separate research studies examining the impacts of implementing proficiency-based diploma systems within the immediate and wider contexts of public schooling in Maine. The first study, presented in February 2018, included case studies of high schools to examine the practices, challenges and facilitators as well as the perceptions of high school educators and administrators about meeting the needs of students and their district's requirements for earning a proficiency-based diploma. That report included a synthesis of key findings to date and a summary of current related literature. This second study used survey methodology to identify levels of progress and attitudes towards implementation of Maine's proficiency-based diploma policy and related education approaches from PK-12 educators in public schools. Prior research has shown an important distinction between teacher beliefs about proficiency-based and standards-based educational practices in general and the specific state policy requirement to award high school diplomas only to students demonstrating proficiency. This survey study focused primarily on the latter. As a companion study, it does not reiterate the background and contextual information already provided in the February 2018 report. Results of this exploratory survey of a sample of 442 Maine PK-12 public school teachers were consistent with conclusions in prior research that practitioners vary widely in their perceptions of implementation progress, necessary resources, and attitudes regarding proficiency-based diploma systems. The range of responses likely stems from several factors including the diverse conditions of individual schools/districts/communities, variation in underlying teacher beliefs, and the specific situations present across different grade levels, content areas, and/or programs. In all, the spring 2018 survey of teachers provides a snapshot of the complex implementation of a far-reaching state policy. It reveals substantial progress and also areas of tension in efforts to ensure that Maine students who earn high school diplomas have met state learning expectations. Teacher feedback suggests that there is need for additional work.