This chapter investigates the crucial roles that syllables play in Korean lexical processing, with a focus on their function as sub-lexical access units in the recognition of words and Eojeols. We analyzed the distributional patterns of orthographic and phonological syllables, examining their respective influences on visual word recognition, syllable frequency effects, and neighborhood size. The chapter suggests the Korean Orthographic-Phonological Syllable Access Model (hereafter K-OPSAM), a novel framework that underscores the importance of phonological syllables as the core access units in the Korean lexicon. According to K-OPSAM, words and Eojeols that share the same initial phonological syllable form interconnected networks, significantly influencing visual word recognition. The model also highlights the role of syllable frequency and neighborhood effects, offering deeper insights into the mechanisms of Korean lexical access and contributing to broader Korean language research.