The rigid framework for interpreting any “code of rules” significantly limits the theoretical aspects of doing research on them and requires a special explanation in relation to orthography as a section of linguistics, especially when there are several national variants of the literary language. The relevance of the study is substantiated by the urgent need for a theoretical description of the corpus of the most significant concepts of spelling used in teaching Russian in Belarus and creating a strategic plan for introducing innovations in spelling; the need to record changes in definitions determined by the transition to convergent learning; the influence of a complex of linguistic and extralinguistic factors, and the development of optional arguments for the codification of the Belarusian national version of the Russian language. The aim of the study is to determine the parameters and specifics of the theory of orthography in educational literature for teaching Russian in the Republic of Belarus. The material of the study contained the definitions and language illustrations of the main concepts of the theory of orthography (spelling, spelling rule, orthogram, spelling principle, spelling error, spelling norm, etc.) in textbooks and manuals on the Russian language for higher education institutions of the Republic of Belarus published from 2000 to 2024. The methods of parameterization and comparison, logical-linguistic and lexical-semantic analysis were used. The authors revealed that both specialized educational publications devoted only to spelling and comprehensive publications where spelling is part of the educational material lack the theoretical and meta-linguistic apparatus of either a significant part or the entire necessary base of the theory of orthography. There are different approaches to the positioning of orthographic terminology that coexist in various educational publications. This is mainly an orientation towards outdated traditions, the absence of modern concepts (such as “orthographic activity”, “orthographic picture of the language”, etc.). The theory of orthography in educational literature on the Russian language for higher educational institutions of the Republic of Belarus is based, as a rule, on the modern rules of Russian spelling, but is characterized, on the one hand, by innovative specificity, and on the other hand, by their conservative positioning in writing practice. This indicates different approaches to the formation of the orthographic linguistic personality, orthographic linguistic and metalinguistic consciousness of Belarusians studying the Russian language. The main principles of modern theory of spelling development should take into account orthographic innovations and national and cultural specificity in teaching the Russian language in higher educational institutions of the Republic of Belarus.