Digraph, often misspelled as diagraph, may refer to:

• Digraph (orthography), a pair of characters used together to represent a single sound, such as "nq" in Hmong RPA
• Ligature (writing), the joining of two letters as a single glyph, such as "æ"
• Digraph (computing), a group of two characters in computer source code to be treated as a single character
• A directed graph, in graph theory
• Digraph, a component of a CIA cryptonym, a covert code name
• Digraph, a two-letter ISO 639-1 language code

• Digraphia, use of multiple complete writing systems for one language.
• Digram (disambiguation) / Digramme
• Bigram
• Trigraph (disambiguation)
• Multigraph (disambiguation)
• Unigraph
• wikt:Diagraph, a combination of a protractor and a scale ruler