Flohwalzer (German: ['floːvaltsər] ^ⓘ, German for "Flea Waltz") is a simple piano piece, often one of the first learned because its fingering is simple and it allows beginners to perform a piece that is harmonically and rhythmically pleasing.

Despite its name, the piece is not a waltz in triple meter (³
₄), as it has a time signature in duple meter (²
₄) and is closer to a polka or galop. The composer is unknown. In a parody of musicology writing, Eric Baumann attributes the piece to Ferdinand Loh, but this is obviously a joke ("F. Loh" = Floh, flea in German). The piece is notated in the identically sounding keys of F-sharp major or G-flat major, because most of the piece's notes are played on black keys in those keys, making the fingering easier.

The piece is known all over the world.

According to an article by Hiromi Oketani in the Osaka Shoin Women's College Annual for 1994, it is known in Japan as "Neko Funjatta" (ねこふんじゃった; I Stepped on the Cat), in Spain as "La Chocolatera", in the Netherlands as "Vlooienmars" (Flea March), in French-speaking countries as "Valse des puces" (Flea Waltz), in Russia as Russian: Собачий Вальс, romanized: Sobachiy Val's, lit. 'Dog Waltz', in Poland as "Kotlety" (Cutlet), in Bulgaria as "Koteshki Marsh" (Cat March), in Hungary as "Szamárinduló" (Donkey March), and in Mallorca as "Polca de los Tontos" (Fools' Polka). In Mexico, it is called "Los Changuitos" (The Little Monkeys), in Finland "Kissanpolkka" (Cat's Polka), in the Czech Republic "Prasečí valčík" (Pig Waltz), in Slovakia "Somársky pochod" (Donkey March), and in Korean "고양이 춤" (Cat Dance).

In China, it is called "跳蚤圆舞曲" (Flea Waltz).

In the United Kingdom, the melody is often called "Chopsticks", not to be confused with "Chopsticks" by Euphemia Allen.

In Taiwan, it is known as "踩到貓兒" (Stepped on a Cat).

In Chile, it is known as "La Polka de los perros" (Dogs' polka).