The bills were approved by the majority as Senate Chairman Sadiq Sanjrani read out the clauses of the bills.
Only a small minority consisting of Jamaat-e-Islami, National Party, and Pakhtunkhwa Milli Awami Party opposed the bill.
The bills included the Pakistan Army (Amendment) Bill, 2020, the Pakistan Air Force (Amendment) Bill, 2020, and the Pakistan Navy (Amendment) bill, 2020.
The bill shall now be sent to President Arif Alvi, whose signature would be required to make it an act of parliament.
On Tuesday, the National Assembly had approved the bills, with even the major opposition parties, the PPP and PML-N supporting the bill. Some opposition lawmakers, including those from JI, JUI-F and representatives from Waziristan, Mohsin Dawar and Ali Wazir, opposed the bill in the lower house of the parliament.