What is the number of syllables in each line in a haiku poem?

5 for the first line,

7 for the second line,

5 for the last line.

Note that in a Japanese-language haiku, the Japanese actually count something a little different called "morae" (singular "mora"). Japanese has vowels of double length, for example, which count as two morae, and the Japanese "N", when it stands by itself in a Word, counts as another. The Word tempura (天ぷら in Japanese, or てんぷら) is four morae (not three), because it is written te - n - pu - ra.