On 31 December 2023, Rohan Dennis was involved in a fatal incident in which a vehicle he was driving struck and killed his wife, Olympian Melissa Hoskins, outside their home in Adelaide.

[17] He also placed second in the Circuit de la Sarthe,[16] and the Commonwealth Games time trial behind England's Alex Dowsett.

[20] Dennis started the 2015 season at home in Australia, finishing second at the Australian National Time Trial Championships, before winning a stage on his way to the overall victory at the Tour Down Under.

[24] Dennis was selected to ride the Tour de France as part of the BMC Racing Team squad supporting Tejay van Garderen.

[32] He then won the sixth stage individual time trial at May's Tour of California,[33] and ultimately finished the race in second overall, behind Julian Alaphilippe.

[34] He was a contender for a medal in the road time trial at the Olympic Games in Rio de Janeiro, but a broken handlebar forced him to change bikes, finishing fifth on the day.

[41] Dennis retained his Australian National Time Trial Championships title in January, finishing almost a minute clear of his next closest competitor, Luke Durbridge.

[60] In August 2018, it was announced that Dennis would join Bahrain–Merida in 2019 on a two-year deal, making the move from BMC Racing Team alongside team-mates Damiano Caruso and Dylan Teuns.

[61] He made his first start in team colours at the Australian National Time Trial Championships, where he was beaten to the title by Luke Durbridge.

[62] He did not win until June's Tour de Suisse, when he won the opening individual time trial stage, on his way to an overall finish of second place behind Egan Bernal.

[66] In an interview he subsequently gave in January 2020, Dennis stated that he left the Tour de France as his mental health was suffering due to difficulties with the team, and he feared that this would have a knock-on effect on his marriage.

[75] Dennis took his first victory with the Ineos Grenadiers at the 2021 Volta a Catalunya, winning the second stage – an individual time trial – in Banyoles.

[81] His last start of the season was at the Tour of Britain, finishing sixth overall following the victory for the Ineos Grenadiers in the team time trial on stage three.

[84] He led the Tour de Romandie for four days,[85] before dropping to eighth overall on the final individual time trial stage, having lost more than two minutes to eventual winner Aleksandr Vlasov.

[86] Later in the season, Dennis won the gold medal in the road time trial at the Commonwealth Games, finishing almost half a minute clear of Fred Wright and Geraint Thomas, the latter having been delayed by a crash.

[90] He supported general classification victories for Jonas Vingegaard at O Gran Camiño and the Tour of the Basque Country, and for Primož Roglič at the Giro d'Italia.

[92] In May 2017, Dennis' partner, fellow racing cyclist Melissa Hoskins, announced the couple's engagement as well as her retirement from competition.

[94] Hoskins gave birth to their first child, a son, later that year, two and a half weeks after Dennis won his first World Time Trial Championship.