With 13 games of the Premier League season to go, United are fifth in the table and six points behind neighbours Manchester City in fourth place.
When asked whether failure to qualify for the Champions League, which United exited at the group stage this season, would affect his future, Van Gaal told reporters: "It's not a question for me, it's a question for the board of Manchester United, you have to put it to them.
"I have a contract for three years and you know that."
The club have a chance to close the gap on those above them this weekend as they travel to 19th-placed Sunderland before the top four play each other on Sunday - Arsenal (3rd) vs. Leicester City (1st) and Man City (4th) vs. Tottenham Hotspur (2nd).
"We don't have to look to our competitors, you have to win your own matches first, and that's also why we were so frustrated that we lost two points against at Chelsea," added Van Gaal.
United can also qualify for the Champions League if they win the Europa League, with the first leg of their last-32 tie against Danish side FC Midtjylland on Thursday.
If Van Gaal is removed from his post, then former Chelsea boss Jose Mourinho is widely expected to replace him at the helm. When asked about reports that United and Mourinho have already held talks, Van Gaal said that he did not believe the rumours.