Linda Reynolds sued Ms Higgins over a series of social media posts the ex-Liberal senator believed damaged her reputation.
The Western Australian Supreme Court in August found the posts were defamatory and awarded damages of $315,000 plus $26,109 interest to Ms Reynolds.
Ms Higgins was also ordered to pay 80 per cent of Ms Reynolds' legal costs, which are yet to be determined, in a judgment published last week.
The former political staffer is appealing the damages award and the costs order, according to documents filed in the WA Court of Appeal on Wednesday.
She's also seeking to challenge the finding that she breached a 2021 deed of settlement between the pair with an Instagram post referring to her being a defamation victim.
Ms Higgins previously apologised to Ms Reynolds after the former defence minister emerged victorious from the duo's high-profile five-week defamation trial, which ended in September 2024.
Justice Paul Tottle found Ms Higgins' social media posts carried an array of imputations.
They included Ms Reynolds engaged in a campaign of harassment against Ms Higgins, mishandled her rape allegation and engaged in questionable conduct during Bruce Lehrmann's aborted criminal trial for rape.
Justice Tottle's 360-page judgment made factual findings about the events involving Ms Reynolds and Ms Higgins, including her alleged 2019 rape and the events in the years after it.
Ms Higgins made 26 false or misleading statements in media interviews after her alleged sexual assault, it said.
She alleges former co-worker Lehrmann raped her in the senator's ministerial suite.
A Federal Court judge overseeing a defamation case launched by Lehrmann against Network Ten found Ms Higgins was, on the balance of probabilities, raped by her former co-worker in the office.
Lehrmann is appealing that finding.
He has always denied the rape allegation and his criminal trial was derailed by juror misconduct.
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