Knowledge about Language (KaL) is an important part of L1 language education around the world. A controversial
part of KaL is grammatical or syntactic knowledge, i.e., knowledge about the form, meaning and use of sentences and phrases. In
the current international discourse on L1 grammar teaching, grammar is principally motivated by the desire to enhance students’
literacy development, befitting the communicative turn in mother tongue education and following high quality research which has
shown that contextualized grammar teaching can impact on students’ writing development. However, there are also other potentially
meaningful reasons to teach grammar, which remain underresearched and underdiscussed in curriculum discussions: (1) the general
importance of language justifies that L1 speakers understand how their language works; (2) grammar teaching provides more insight
into the workings of the human mind; (3) grammar teaching can be used to facilitate students’ reasoning and stimulate their
critical thinking abilities. These reasons for teaching grammar do not necessarily relate to literacy development; rather, they
pertain to a general conceptual importance of knowledge about grammar. This paper explores these arguments and argues, partly
based on empirical evidence from recent research, that knowledge-related rationales deserve a more prominent place in curriculum
discussions about grammar teaching.