Northampton had the better of a scrappy first half in which both defences were on top and chances were few and far between.
Aaron Phillips tested Simon Eastwood with a long-range shot and Marc Richards headed onto the roof of the net for the Cobblers.
Matt Taylor also had a free-kick deflected over, and from his ensuing corner, the unmarked Zander Diamond headed off target.
Michael Smith headed wide for the hosts before Oxford began to offer more of a threat in the final third, with Conor McAleny curling an effort wide and Antonio Martinez firing a shot over the bar.
After the restart Liam Sercombe fired wide for Oxford before Northampton missed a glorious opportunity to break the deadlock when they were awarded a penalty, only for Taylor's spot-kick to be superbly saved by Eastwood.
Northampton still sensed the breakthrough, but Richards fired into the side-netting and Paul Anderson failed to convert from Phillips' excellent cross.
Oxford had a couple of good chances late on as Curtis Johnson had a shot tipped onto the bar by Smith, who then foiled a Kane Hemmings effort.
Match report supplied by the Press Association.
Match ends, Northampton Town 0, Oxford United 0.
Second Half ends, Northampton Town 0, Oxford United 0.
Foul by Michael Smith (Northampton Town).
Curtis Nelson (Oxford United) wins a free kick in the defensive half.
Attempt blocked. Marc Richards (Northampton Town) right footed shot from the centre of the box is blocked.
Attempt saved. Michael Smith (Northampton Town) header from very close range is saved in the top centre of the goal.
Zander Diamond (Northampton Town) wins a free kick in the defensive half.
Foul by Kane Hemmings (Oxford United).
Corner,  Oxford United. Conceded by Adam Smith.
Attempt saved. Robert Hall (Oxford United) left footed shot from the centre of the box is saved in the bottom left corner.
Foul by Marc Richards (Northampton Town).
Curtis Nelson (Oxford United) wins a free kick in the defensive half.
Attempt missed. Michael Smith (Northampton Town) header from the centre of the box is too high.
Substitution, Oxford United. Joe Skarz replaces Josh Ruffels because of an injury.
Attempt saved. Liam Sercombe (Oxford United) right footed shot from outside the box is saved in the top centre of the goal.
Philip Edwards (Oxford United) wins a free kick in the defensive half.
Foul by Gregg Wylde (Northampton Town).
Paul Anderson (Northampton Town) wins a free kick in the defensive half.
Foul by Robert Hall (Oxford United).
Attempt saved. Joe Rothwell (Oxford United) right footed shot from the left side of the box is saved in the top right corner.
Corner,  Oxford United. Conceded by Lewin Nyatanga.
Attempt blocked. Philip Edwards (Oxford United) right footed shot from outside the box is blocked.
Paul Anderson (Northampton Town) is shown the yellow card for a bad foul.
Marvin Johnson (Oxford United) wins a free kick on the left wing.
Foul by Paul Anderson (Northampton Town).
Attempt saved. Zander Diamond (Northampton Town) header from the centre of the box is saved in the bottom right corner.
Corner,  Northampton Town. Conceded by Curtis Nelson.
Substitution, Northampton Town. Brendon Moloney replaces Aaron Phillips.
Corner,  Northampton Town. Conceded by Cheyenne Dunkley.
Attempt saved. Liam Sercombe (Oxford United) left footed shot from the centre of the box is saved in the top centre of the goal.
Substitution, Oxford United. Robert Hall replaces Conor McAleny.
Attempt saved. Liam Sercombe (Oxford United) right footed shot from outside the box is saved in the top centre of the goal.
Corner,  Oxford United. Conceded by Paul Anderson.
Foul by Marc Richards (Northampton Town).
Cheyenne Dunkley (Oxford United) wins a free kick in the attacking half.
David Buchanan (Northampton Town) wins a free kick on the right wing.
Foul by Kane Hemmings (Oxford United).
Corner,  Oxford United. Conceded by Zander Diamond.
Corner,  Oxford United. Conceded by David Buchanan.
Substitution, Northampton Town. Gregg Wylde replaces Jak McCourt.
Northampton missed a penalty and both goalkeepers were in fine form as they played out a goalless stalemate with Oxford at Sixfields.