In the original Japanese release of Naruto, (Da)ttebayo! (「(だ)ってばよ!」) is Naruto Uzumaki's catch phrase. He uses it at the end of most of his sentences as a way of making his speech unique. Naruto inherited this from his mother, Kushina Uzumaki, who would instead end her sentences with (Da)ttebane (「(だ)ってばね」) when she got excited or angry, something she had hoped — albeit unsuccessfully – that her son would not inherit. Naruto's son, Boruto Uzumaki, also inherited this verbal tic, ending sentences with (Da)ttebasa (「(だ)ってばさ」).
Dattebayo has no literal English translation; however, "Believe It!" was used in the English dub whenever Naruto is making a big statement to keep a similar tone in the English version of the series. It is also used to match the lip movements from the original Japanese release. Around the start of the Chūnin Exams, however, "Believe it" fell out of use. It is translated also as "Do you get what I'm saying?", which he uses before the fight with Zabuza Momochi, where it was hard to match the lip movements when translated into English.
- Since chapter 492 and Naruto: Shippūden episode 243, 'Dattebayo" has been translated as "you know" and more loosely as "ya know" when used by Killer B. Kushina's '(Da)ttebane' has been translated in a likewise manner.
- In the Japanese version of episode 101, when Sakura tries to scare away the Moya Triad, she says "Dattebayo!"