Boris Johnson and Jeremy Hunt face a series of hurdles in the race to Number 10 over the coming weeks.
Here are some of the key events:
Saturday June 22
The first hustings for members, organised by Conservative Campaign Headquarters, will take place in Birmingham, hosted by broadcaster Iain Dale.
Mr Johnson and Mr Hunt will each make a short pitch to the audience, followed by questions from Dale and the Tory members at the event.
Conservative Campaign Headquarters (CCHQ) has organised a total of 16 hustings starting with the Birmingham event.
They include a “digital hustings” on June 26, with a series of events across England, and one each in Scotland and Wales.
There have been more than 20,000 applications for tickets to the 16 events.
Conservative members should receive their postal ballots.
Mr Hunt and Mr Johnson will go head-to-head in an ITV debate hosted by Julie Etchingham.
The BBC and Sky News also want to hold TV specials involving the two leadership hopefuls.
The final hustings will take place in London.
Week commencing July 22
A new leader will be announced following the ballot of 160,000 Conservative members.
Prime Minister Theresa May will then see the Queen to formally resign and the new leader will be invited to Buckingham Palace to form a government.