The news comes two days after the League One outfit were beaten 5-0 by Bristol Rovers at the Memorial Stadium.
Page issued an apology on Saturday for his post-match remarks, in which he claimed that witnessing his team play was like watching "men against girls".
Northampton are currently 16th in the table following three straight defeats.
The club announced Page's sacking on Monday via their official website, adding a statement from chairman Kelvin Thomas, which read: "We are disappointed to make this decision regarding Rob, however following the recent run of results we feel that a change is necessary.
"Rob has always been extremely professional throughout his time and has only ever wanted the club to be successful. It was always going to be a very tough challenge following last year and the expectation that created, so we thank him for his efforts and we wish him very well for the future.
"Paul Wilkinson will take temporary charge of the team whilst we begin discussions with potential replacements, and all focus will now shift to preparations for Saturday's important fixture against Scunthorpe United here at Sixfields."
Page spent less than eight months in charge of Northampton.