In the email, Rubio writes that a victory for Gomez would be a "huge step" toward replacing Senate Majority Leader Harry Reid (D-Nev.) with a Republican majority leader.
"Gomez is a business leader and a former Navy Seal who knows what it means to fight for our freedoms. Now he's fought within inches of a major political upset that could have national implications — which is why liberals have pulled out all the stops," Rubio writes in the fundraising email from Reclaim America PAC. "Gomez is currently facing a massive onslaught of Democratic special interest money. Everyone from President Obama to Harry Reid to a host of Hollywood liberals have pitched in to help defeat Gomez. Now it's time to come to his aid."
The email comes just three weeks ahead of the special election for Secretary of State John Kerry's former Senate seat.
Republicans in Massachusetts are reportedly spending $400,000 on ad spending in support of Gomez.
High profile political figures have also campaigned on behalf of Markey and Gomez, respectively. Sen. John McCain (R-Ariz.) campaigned for Gomez and first lady Michelle Obama attended a recent fundraiser for Markey.