转写（英语：transliteration）是将一个拼音文本系统的字符，按照一个字符对照表，忠实地，对号入座地转换成另一个拼音文本系统的字符的过程（包括基础字符的附加符号和用双字符表示的单音素），转写在文本系统之间进行。

例如拉丁字母、西里尔字母都是由希腊字母转变而成，所以希腊字母α在转写成其他语言时，便变成了西里尔字母ａ及拉丁字母a。

汉语拼音一般不作文本使用，不过中华人民共和国政府制作了维、蒙、藏文本母和中国盲文点字对汉语拼音字母的对照表。维、蒙、藏与汉语拼音字母的对照表见于《少数民族语地名汉语拼音字元音译转写法》。盲文点字对汉语拼音字母的对照表见于《中国盲文》（GB/T 15720-1995）。

Transliteration is the conversion of a text from one script to another.

For instance, a Latin transliteration of the Greek phrase "Ελληνική Δημοκρατία", usually translated as 'Hellenic Republic', is "Ellēnikḗ Dēmokratía".

Transliteration is not concerned with representing the sounds of the original, only the characters, ideally accurately and unambiguously. Thus, in the above example, λλ is transliterated as 'll', but pronounced /l/; Δ is transliterated as 'D', but pronounced 'ð'; and η is transliterated as 'ē', though it is pronounced /i/ (exactly like ι) and is not long.