Fiona Onasanya has been jailed for three months for lying to police to avoid a speeding ticket.
The former Labour MP for Peterborough was found guilty of perverting the court of justice following a retrial in December.
Onasanya took the marginal seat from the Tories with a majority of just 607 at the 2017 election just 18 months ago.
Parliamentary rules require the removal of an MP who is jailed for 12 months or more so Onasanya will not immediately lose her seat but a recall petition can force a by-election if it is signed by more than 10% of the electorate in the Cambridgeshire seat.
The Old Bailey heard evidence the MP was texting as well as speeding on the evening of Monday July 24 last year, during the summer recess.
The 35-year-old solicitor was clocked going 41mph in a 30mph zone in the village of Thorney near Peterborough.
The prosecution alleged she went on to collude with her brother Festus to avoid a speeding ticket.
The court was told she was sent a Notice of Intended Prosecution (NIP) to fill out, but it was sent back naming the driver as Aleks Antipow, an acquaintance of Festus, who was away visiting his parents in Russia.
Festus, 34, from Cambridge, pleaded guilty to three counts of perverting the course of justice over speeding, including for the July 24 incident.
The siblings were sentenced at the Old Bailey by Mr Justice Stuart-Smith on Tuesday.
In the wake of the guilty verdict in December, Onasanya was expelled from the Labour Party and has launched an appeal against her conviction.