MB, who cannot be named, is currently not entitled to the pension because she refused to have her marriage annulled following her gender reassignment, insisting her decision to wed was a commitment made "in the sight of God".
Transgender people were allowed in 2005 to apply under the 2004 Gender Recognition Act for a "gender recognition certificate", however, this did not include a married person who did not have their marriage annulled following their gender change.
Without a gender recognition certificate, the 66-year-old is unable to able for the female state pension.
MB, who began to live as a woman in 1991 before undergoing the procedure four years later, has been married to her wife for 38 years; the couple have had two children together.
After turning 60, MB applied in 2008 for a state pension but was denied by the Department for Work and Pensions because she was a man and would have to wait until she reached the male pension age of 65.
Judges at the Court of Appeal unanimously ruled the decision was not discriminatory and didn't go against the principle of equal treatment, prompting MB to take her case to the Supreme Court.
Court of Appeal judge Lord Justice Maurice Kay said: "The appellant does not wish to have her marriage annulled. She and her wife have lived as a married couple for 38 years and do not wish to change.
"Also, as a Christian she says that she and her wife feel married in the sight of God. Accordingly, she has not applied for a gender recognition certificate, and so far as the law is concerned she remains a man."