Party sources said that after the oath-taking ceremony, a new Cabinet is expected after Diwali on Sunday.
Finance Minister Nirmala Sitharaman and BJP General Secretary Arun Singh will attend the meeting as observers at the UT Guest House.
After the election of the Legislature Party leader in Chandigarh, the party will stake claim for the formation of the next government in alliance with the less than 12-month old Jannayak Janata Party (JJP)-led by Dushyant Chautala.
The BJP, which is six short of a majority, on Friday night sealed the deal for government formation with the JJP with its leader Dushyant or his mother Naina Chautala to be the Deputy Chief Minister.
The announcement of the post-poll alliance was announced by the Home Minister and BJP President Amit Shah at his residence in New Delhi.
At Shah's residence, Khattar was also present along with BJP working President J.P. Nadda.
"The two parties have decided to form the government to respect the mandate of the people. It has been decided that the Chief Minister will be from the BJP and the Deputy CM from the JJP," Shah said
On his part, Dushyant said his party has decided to support the BJP "for the stability of the government in Haryana".
The BJP, which had secured the support of seven Independents as well as former minister Gopal Kanda, has now decided not to include the latter's name in the list of MLAs supporting it, after the party faced the large-scale ire on the social media for taking his support.
Kanda is accused of abetting the suicides of his then airline's employee, Geetika Sharma, in 2012, and her mother in 2013.
The JJP, which broke away from the state's once major regional Indian National Lok Dal (INLD) owing to family disputes, won 10 seats, while the Congress won 31 seats.
Eight BJP ministers lost the polls along with state party chief Subhash Barala.
BJP's outgoing ministers Captain Abhimanyu, O.P. Dhankar, Ram Bilas Sharma, Kavita Jain, Krishan Lal Panwar, Manish Grover, Karan Dev Kamboj and Krishan Kumar Bedi all faced humiliating defeats.
( With inputs from IANS )