Codex Boernerianus, designated by Gp, G3 or 012 (in the Gregory-Aland numbering of New Testament manuscripts), α 1028 (in the von Soden numbering of New Testament manuscripts), is a small New Testament manuscript made of parchment which contains the majority of the Pauline epistles. Using the study of comparative writing styles (paleography), the manuscript has been dated to the 9th century CE. The name of the codex derives from the theology professor Christian Frederick Boerner, to whom it once belonged. The manuscript has several gaps.

The Pauline epistles, also known as Epistles of Paul or Letters of Paul, are the thirteen books of the New Testament attributed to Paul the Apostle, although the authorship of some is in dispute. Among these epistles are some of the earliest extant Christian documents. They provide an insight into the beliefs and controversies of early Christianity. As part of the canon of the New Testament, they are foundational texts for both Christian theology and ethics.