Fierravanti-Wells left the Australian parliament's frontbench after voting for Peter Dutton in a leadership vote on Wednesday. Fierravanti-Wells said Turnbull had alienated the party's base.
The Australian Broadcasting Corporation reported that Fierravanti-Wells was also unhappy about the way she was treated after she made contentious comments about China's relationship with the Pacific.
"I was disappointed that my frank and forthright comments regarding China were criticised," she wrote in her resignation letter.
"I am pleased that subsequent events and media scrutiny have fully vindicated me raising these concerns," Fierravanti-Wells claimed.
In January, Fierravanti-Wells stirred controversy when she accused Beijing of building "roads to nowhere"in the Pacific while saddling small nations with unsustainable debt.
Bishop did not criticise Fierravanti-Wells' comments, but she pointedly did not back them up either.
When asked today if she felt she'd been "hung out to dry" by the party leadership, Fierravanti-Wells told the ABC she "would have liked more support".
"That was certainly the perception, and that was certainly my view. And that was the perception of some of my colleagues as well," she said.
"But the reality is that we're in politics. That's fine."
In January, China's Foreign Ministry responded angrily to Fierravanti-Wells' intervention in the debate, which also drew criticism from some Pacific leaders.
In 2015 Senator Fierravanti-Wells declared that the "silent majority" would shut down proposal that same-sex marriage could be a reality in Australia. She also previously said: "Most Australians would find these concepts repugnant, abhorrent and destructive to our social fabric."
In her resignation letter Fierravanti-Wells said the marriage debate had led to the party's base "being eroded". It was a concern she had previously raised when delivering a speech to the National Press Club in 2015.
Her views on marriage equality were out of step with both sides of politics.