A tone language, or tonal language, is a language in which words can differ in tones (like pitches in music) in addition to consonants and vowels.

Many languages, including Chinese, Vietnamese, Thai, Lao, Hmong, Punjabi, Sylheti, Chittagonian, Yorùbá, Igbo, Luganda, Ewe, and Cherokee are tonal. Other languages, including Indo-European languages such as English and Hindi, are not considered tone languages but can use tone in different ways.

In some languages, it is pitch accent that is important instead. A word's meaning can then change if a different syllable is stressed. Examples include Ancient Greek, Hebrew, Swedish, Norwegian, Serbo-Croatian, Lithuanian, and some Asian languages like Japanese and Korean. However, pitch accent is different from tones.

Some tones may sound alike to people who do not speak a tone language. They are the most difficult part of learning a tone language for those people.