The Bengali script or Bangla alphabet (Bengali: বাংলা বর্ণমালা, romanized: Bāṅlā bôrṇômālā also called Gauḍa script) is the standard writing system used to write the Bengali language, and has historically been used to write Sanskrit within Bengal. An estimated 300 million people use this syllabic alphabet, which makes it the 5th most commonly used writing system in the world. It is the sole national script of Bangladesh and one of the official scripts of India, specifically used in the Indian states of West Bengal, Tripura and the Barak Valley of Assam. The script is also used for the Meitei language in Manipur, defined by the Manipur Official Language (Amendment) Act, 2021.

From a classificatory point of view, the Bengali writing system is derived from the Brahmi script. It is written from left to right. It is an abugida, i.e. its vowel graphemes are mainly realised not as independent letters, but as diacritics modifying the vowel inherent in the base letter they are added to. There are no distinct upper and lower case letter forms, which makes it a unicameral script. The script is characterized by many conjuncts, upstrokes, downstrokes, and other features that hang from a horizontal line running along the tops of the graphemes that links them together called matra(মাত্রা). The punctuation is all borrowed from 19th-century English, with the exception of one.

The Bengali script can be divided into vowels and vowel diacritics, consonants and conjunct consonants, diacritical and other symbols, digits, and punctuation marks. Vowels and consonants are used as letters and also as diacritical marks.

The Bengali script has a total of 11 vowel graphemes, each of which is called a স্বরবর্ণ swôrôbôrnô 'vowel letter'. The swôrôbôrnô's represent six of the seven main vowel sounds of Bengali, along with two vowel diphthongs. All of them are used in both Bengali and Assamese languages.

The table below shows the vowels present in the modern (since the late 19th century) inventory of the Bengali alphabet:

Consonant letters are called ব্যঞ্জনবর্ণ bænjônbôrnô 'consonant letter' in Bengali. The names of the letters are typically just the consonant sound plus the inherent vowel অ ô. Since the inherent vowel is assumed and not written, most letters' names look identical to the letter itself (the name of the letter ঘ is itself ghô, not gh).

Clusters of up to four consonants can be orthographically represented as a typographic ligature called a consonant conjunct (Bengali: যুক্তাক্ষর/যুক্তবর্ণ juktakkhôr/juktôbôrnô or more specifically যুক্তব্যঞ্জন). Typically, the first consonant in the conjunct is shown above and/or to the left of the following consonants. Many consonants appear in an abbreviated or compressed form when serving as part of a conjunct. Others simply take exceptional forms in conjuncts, bearing little or no resemblance to the base character.

Often, consonant conjuncts are not actually pronounced as would be implied by the pronunciation of the individual components. For example, adding ল lô underneath শ shô in Bengali creates the conjunct শ্ল, which is not pronounced shlô but slô in Bengali. Many conjuncts represent Sanskrit sounds that were lost centuries before modern Bengali was ever spoken as in জ্ঞ. It is a combination of জ ǰô and ঞ ñô but it is not pronounced "ǰñô" or "jnô". Instead, it is pronounced ggô in modern Bengali. Thus, as conjuncts often represent (combinations of) sounds that cannot be easily understood from the components, the following descriptions are concerned only with the construction of the conjunct, and not the resulting pronunciation.