The Graduate Diploma in Law/Postgraduate Diploma in Law/Common Professional Examination (GDL/PGDL/CPE) is a postgraduate law course in England and Wales that is taken by non-law graduates (graduates who have a degree in a discipline that is not law or not a qualifying law degree for legal practice) wishing to become either a solicitor or barrister in England and Wales. The course allows non-law students to convert to law after university (exceptions exist for non-graduates depending on circumstances); it is commonly known as a "law conversion course". Regulated by the Solicitors Regulation Authority, the course is designed as an intense programme covering roughly the same content as a law degree LL.B (Hons) and the main goal is to allow people with a greater variety of educational backgrounds into the legal profession.

Most GDL/PGDL courses award a diploma and are thus often titled Common Professional Examination (CPE).

The GDL/PGDL is one (full-time) or two (part-time) years long, and successful candidates may proceed to either the Legal Practice Course (LPC) for solicitors or the Bar Professional Training Course (BPTC) for barristers. It is regulated by the Law Society of England and Wales with admissions handled through the Central Applications Board.

Some law students study for four years (rather than three years, although this is usually only the case for students taking a combined law degree with the LPC, or for those whose courses include study abroad), making it possible for both non-law and law graduates of the same starting year to finish at the same time, with the CPE providing the "foundations of legal knowledge".