Neymar, 30, played in the past two World Cups but has yet to win a major title with the national team.
"I'll play like it's the last," Neymar told Globo. "I talk to my father, we always talk, to play each game as if it were the last because you don't know what will happen tomorrow.
"I can't guarantee that I'll play another [World] Cup. I honestly don't know. I'll play like it's the last. Maybe I'll play another one, maybe not. It depends. There's going to be a coaching change and I don't know if that coach will like me."
Brazil coach Tite will step down after the tournament in Qatar and his replacement has yet to be named.
The Canarinha have won a record five World Cups but haven't won the trophy since 2002.
"I've already built a long history in the national team and, for sure, I want to finish it well," Neymar added.
Neymar, who made his debut with the senior team at 18, is two goals from equalling Brazil's all-time top scorer Pele.
"It's more than I imagined, than I dreamt," he said. "I never thought about numbers, I never wanted to overtake anyone, break a record. I always just wanted to play football.
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"Pele is the reference. Pele is football. Pele is practically everything for our country. The respect and admiration I have for him is enormous."
Brazil have not lost a game since the Copa America final defeat at home to bitter rivals Argentina last year.
Neymar also heads into the tournament in fine form with 15 goals and 12 assists in 19 appearances for Paris Saint-Germain but said he is not seeking individual glory in Qatar.
"I want to play this [World] Cup, dedicate myself to it, because I'm sure we have the potential to go very far," he added. "Although a lot of people don't believe in us, we will prove otherwise. I see that this national team has a lot of good things, and I see that we can go very far.
"I'm happy. I like to play football and I like to win. I like to be better than I am every day. I like helping my teammates, which is the main thing. I hope my name is engraved in football history."