This is the first time that Uddhav Thackeray-led party is fighting Goa polls in an alliance with local party.
Sena, a key constituent of NDA, is the oldest ally of BJP and also a junior partner in Centre and Maharashtra governments.
The announcement for the tie-up was made by Sena MP Sanjay Raut and GSM president Anand Shirodkar.
"Five seats would be contested by Shiv Sena, where we will whole-heartedly support them. The alliance is formed as both the political parties are like-minded and have welfare of Goa at their heart," Shirodkar told reporters today.
Sena would field its candidates on Pernem, Thivim, Saligao, Cuncolim and Vasco constituencies, all represented by BJP legislators, out of total 40 seats.
Goa will go to polls next year.
Shirodkar said the GSM-Shiv Sena combine is still open for alliance with Maharashtrawadi Gomantak Party (MGP).
"We are still waiting to know the mind of MGP. GSM's core committee has given a deadline till November 30 for MGP members to decide and revert," he said.
GSM is yet to decide on number of seats it will contest in its maiden election.
Meanwhile, GSM announced its alliance with newly-formed Praja Party, though contours like seat-sharing are yet to be worked out.
Velingkar had floated GSM after the BJP refused to heed the demand of Bharatiya Bhasha Suraksha Manch (BBSM) to withdraw grants to English medium schools in Goa.
BBSM has been demanding that local language should be made as the Medium of Instruction (MoI) in elementary education across Goa.
Sena had given its in-principle approval to forge a pre- poll alliance with GSM after party president Uddhav and Velingkar held a meeting at a five-star resort near here last month.