The body, which represents university and college students across the country, has said young people have a chance to create "decisive change" in this poll.
The union has also called for students to make a plan for voting, as the December 12 poll coincides with many colleges and universities preparing to go into their winter break.
The NUS Scotland president has also pushed for students to ensure they do not lose their vote, saying they are eligible to cast their ballot at either their term time address or at home.
Voters have until Tuesday register for the election.
NUS Scotland president Liam McCabe said: "The deadline is fast approaching and time is running out to ensure students are registered to vote in this crucial general election.
"By being voters, students in Scotland can make the decisive change in this election. But they need to make sure they're registered, and make a plan to use their vote come polling day.
"It only takes five minutes to register and we're calling on all institutions to ensure this is clearly signposted and actively encouraged during classes.
"With polling day coinciding with the festive wind-down, it's crucial that students register and make a plan.
"Students living away from home can vote at either at home or their term-time address on polling day.
"That means thinking ahead, making a plan of where they're going to vote and coming out in their droves to make a change."
NUS Scotland has partnered with the Electoral Commission as part of its "Got Five?" campaign, which urges people to register to vote as well as highlighting the ease of the process.