The impact of linguistic proximity and diglossia on multinational corporations’ visual identity extension strategies in multiple sociolinguistically different markets is investigated. Specifically, this study focuses on a sample of Fortune Global 500 corporations and explores their brand name/slogan extension practices in three distinct linguistic contexts: Turkish, Russian and Arabic. The study reveals that the different levels of linguistic proximity systematically influence brand name adaptation including brand name transliteration, as well as slogan translation and new slogan creation in English. The study also finds that these tendencies non-systematically but significantly vary across the levels of diglossia. Conversely, diglossia systematically influences slogan standardization and new slogan creation in a local language, while the effect of linguistic proximity on these practices is non-systematic.