The Gunners are currently second in UEFA Champions League Group B, one point ahead of Olympiakos but one behind leaders Schalke.
Montpellier are a long way adrift at the bottom and Ramsey is desperate to claim victory at Emirates Stadium in midweek, while he would also love to see Schalke defeat the Greek side in the group's other game.
Ramsey said: "The group is pretty tight at the moment, so yes I think you could say that we have to win this game, and we are at home so hopefully we can do that and put ourselves in a strong position to qualify.
"That is our aim and hopefully we can get the win which puts us in a better position.
"The ideal situation is that we will be qualified before going into the last game. Other matches are completely out of our hands, so we have got to look after our own results, but if Schalke do win, then that would be the preferred choice for us."
A Schalke victory would most likely leave Arsenal looking at second spot in the group, but Ramsey insists they should not fear anyone in the last 16.
"It (second place) has been quite costly in the last few years," the Wales international told Arsenal Media. "We finished second in the group a couple of seasons ago and played Barcelona, so you know you're going to have a strong team if you do finish second.
"But most importantly we need to qualify and if we do, we are confident that we can compete and challenge against any team in the competition."
Montpellier may have picked up just one point from four matches but Ramsey is expecting the Ligue 1 side to provide a stern challenge.
"When we played them in France we were under pressure for periods of the game and we did well to get a result there," he said.
"They have competed against every team and showed they can create and can be a threat, so it will be no pushover.
"Montpellier will want to prove something as well, that they can compete against the best teams, so we will have to be aware of that and be right on top of our game on the day."