Months after the Abbott Government took office, Bishop announced the implementation of a New Colombo Plan which would provide undergraduate students with funding to study in several different locations within the Indo-Pacific. The plan started off in pilot form and after initial success the full program was rolled out in 2015.
In a 2015 speech explaining the Australian Government's measures against ISIS, Bishop compared the psychological underpinnings of ISIS with that of Nazism. Citing Eric Hoffer's seminal work The True Believer, she argued that the declared Caliphate drew from the same source that drove the masses to support Hitler; "Invincibility was—until the US-led airstrikes—all part of its attraction."
In April 2015, Bishop paid an official visit to Iran, following the conclusion of a visit to India. She was the first Australian government minister to visit the country since 2003, having been personally invited by Iran's foreign minister, Mohammad Javad Zarif. They discussed the proposed nuclear deal and issues relating to Iranian asylum seekers in Australia. Bishop wore a headscarf or a hat for the duration of her visit, and did not shake hands with male dignitaries in order to avoid offending local sensibilities. She received some criticism for doing so, with Andrew Bolt rhetorically asking whether she should have "subjugated herself" to Islamic law. Head coverings are not mandatory for foreign women visiting Iran. In response, she said: "As a matter of fact I wear scarves and hats and headgear quite often as part of my everyday wear".
Bishop was involved at the highest level of negotiations with the Indonesian Government in attempts to save the lives of convicted drug smugglers Myuran Sukumaran and Andrew Chan. Demonstrating Australia's opposition to the death penalty, Bishop was widely applauded for the manner in which she conducted negotiations. This was in stark contrast to the criticism faced by Tony Abbott who was ridiculed for remarks he made in regards to foreign aid provided by Australia to Indonesia. Despite the Government's efforts, both Chan and Sukumaran were executed in April 2015. As a result of the executions, Bishop recalled the Australian Ambassador from Indonesia in condemnation of their decision.
By August 2015, Bishop stated that Australia's relationship with Indonesia was "back on track" after privately meeting with the Indonesian Foreign Minister to discuss the fallout from the executions.
In February 2015, in response to rising criticisms of his leadership, Tony Abbott called a spill of leadership positions. Both Julie Bishop and Communications Minister Malcolm Turnbull were reported by the media as considering challenging for the leadership. Opinion poll results consistently showed that both Bishop and Turnbull were preferred by the public to Abbott. Eventually a motion to move a leadership spill fell by 61 votes to 39, and Abbott consequentially remained in office.
On 14 September 2015, Malcolm Turnbull challenged Tony Abbott for the leadership of the Liberal Party. After Turnbull was successfully elected, Bishop defeated a challenge from Kevin Andrews to retain her position as Deputy Leader by 70 votes to 30. Hours before Turnbull's challenge, Bishop had visited Abbott to advise him he had lost the confidence of the Parliamentary Liberal Party. She is said to have intended to vote for Abbott in the leadership vote until he declared her position vacant as well as his, after which she voted for Turnbull. Bishop was retained as Foreign Minister following the formation of the Turnbull Government.
During the internal debate on same-sex marriage which divided the Liberal Party in August 2015, Bishop refused to publicly declare her personal views on the matter. However, her statement that she was "very liberally minded" on the topic was taken by many to be an allusion towards support of same-sex marriage. In a television interview in November 2015, Bishop confirmed that she supported same-sex marriage.
In August 2015, Bishop spoke in favour of holding a plebiscite on the matter, believing that the issue should be put to a democratic vote so that it could no longer distract from the government's policy agenda. This ultimately became the policy adopted by the government. Following the postal plebiscite in 2017, which resulted in a "Yes" vote, Bishop stated that she had voted in support of same-sex marriage.