This article is a list of standard proofreader's marks used to indicate and correct problems in a text. Marks come in two varieties, abbreviations and abstract symbols. These are usually handwritten on the paper containing the text. Symbols are interleaved in the text, while abbreviations may be placed in a margin with an arrow pointing to the problematic text. Different languages use different proofreading marks and sometimes publishers have their own in-house proofreading marks.^[1]

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Depending on local conventions, underscores (underlines) may be used on manuscripts (and historically on typescripts) to indicate the special typefaces to be used:^[2][3]

• single dashed underline for stet, 'let it stand', proof-reading mark cancelled.
• single straight underline for italic type
• single wavy underline for bold type
• double straight underline for SMALL CAPS
• double underline of one straight line and one wavy line for bold italic
• triple underline for FULL CAPITAL LETTERS (used among small caps or to change text already typed as lower case).

• ISO 5776 – Standard symbols for proofreading
• Blue pencil (editing) – Pencil used to show corrections to written copies