This chapter examines the role of pedagogical grammar (PG) in foreign language teaching and learning from a theoretical perspective. PG is positioned at the interface of linguistic grammar and grammar teaching and can be defined as "a system of meaningful structures and patterns that are governed by particular pragmatic constraints". The PG of a language can vary depending on a practitioner's point of view, such as generative or cognitive perspectives, or a unique amalgam of these or other theories. A PG should guide the target learners through a language. At the simplest level, it should assist learners in overcoming so-called global errors, where an utterance hardly makes sense because of the ungrammaticality, while preparing learners to later overcome 'local errors', where an utterance makes sense to some extent despite some incorrect grammar uses. It is only natural that learners will face difficulties when learning grammar.