Downstep is a phenomenon in language where when two syllables have the same tone (for example both have high tone, or both have mid tone), the second syllable is lower in pitch than the first.

Two main kinds of downstep can be distinguished. The first, more usually called automatic downstep, downdrift or catathesis, occurs when high and low tones come in the sequence H L (L) H; then the second high tone tends to be lower than the first because of the intervening low toned syllable. This phenomenon is common in African languages. It has also been argued that it is this same phenomenon which causes English sentences such as I really believe Ebenezer was a dealer in magnesium or I bought blueberries, bayberries, raspberries, mulberries, and brambleberries (if these sentences are pronounced with a falling intonation) to fall gradually in pitch, with each accented syllable (here underlined) slightly lower than the last.