The Thai script is the abugida used to write Thai, Southern Thai and many other languages spoken in Thailand. The Thai alphabet itself has 44 consonant symbols and 16 vowel symbols that combine into at least 32 vowel forms and four tone diacritics to create characters mostly representing syllables.

An abugida – sometimes also called alphasyllabary, neosyllabary, or pseudo-alphabet – is a segmental writing system in which consonant–vowel sequences are written as units; each unit is based on a consonant letter, and vowel notation is secondary, similar to a diacritical mark. This contrasts with a full alphabet, in which vowels have status equal to consonants, and with an abjad, in which vowel marking is absent, partial, or optional – in less formal contexts, all three types of the script may be termed "alphabets". The terms also contrast them with a syllabary, in which a single symbol denotes the combination of one consonant and one vowel.