However, one of the vacant roles remains unfilled after no-one stood for the role of international officer.
The latest by-election came after a string of four resignations from OUSA's executive within a month.
Law student Paul Hunt won the finance officer's role, physical education and bachelor of science student Payal Ramritu is the new welfare officer and Jess McLean was elected as colleges officer, after running unopposed.
Mr Hunt said he would focus on diversifying OUSA's income, as it was reliant on the university for a large majority of its funds.
Ms Ramritu was keen to get the welfare committee running and involve a diverse range of students.
Ms McLean is in her third year at St Margaret's College and was keen to use her experience at the hall of residence to help push for improvements.
