To applause, Ms Truss told Conservative Party members: “I stand here today as the first prime minister of our country to have gone to a comprehensive school.”
However, contrary to her comments, other prime ministers have attended state schools.
Labour's former prime minister, Gordon Brown, attended Kirkcaldy High School, which is now a comprehensive in Fife.
Mr Brown was reportedly taught in a special fast-stream while at the school.
Theresa May attended a girls’ grammar school in Oxfordshire, which was reorganised into a comprehensive school during her education there.
Questioned about the other leaders who went to state schools, Ms Truss’s press secretary said: “My understanding is this is quite complicated and it changed halfway through and comps weren’t actually called comps until the 60s or something like that.
“I’m not going to do a pop quiz on former PMs’ schooling.”
Of the UK's 56 prime ministers, 20 have been educated at Eton College, while a further 13 studied at either Harrow or Westminster School.
Ms Truss continued: "That taught me two things: one is that we have huge talent across our country and two that we’re not making enough of it.
"This is a great country. I’m so proud of who we are and what we stand for, but I know that we can do better and I know that we must do better and that’s why I entered politics.
"I want to live in a country where hard work’s rewarded, where women can walk home safely at night and where our children have a better future."
Ms Truss also referenced her childhood, growing up in Paisley, Scotland, and in Leeds, later in her address to the party conference.
“I’ve seen the boarded-up shops. I’ve seen people left with no hope turning to drugs. I have seen families struggling to put food on the table," she added.
“Low growth isn’t just numbers on a spreadsheet. Low growth means lower wages, fewer opportunities and less money to spend on the things that make life better.”
To help make sure "everywhere and everyone can get on” the prime minister said the country must level up in a "Conservative way".
What is a comprehensive school?
State schools are funded directly by the government or local authority.
Comprehensive schools - which were introduced in the 1940s and have since become widespread- are secondary schools funded by local education authorities, which can also be run by academy trusts.
A comprehensive school is not selective in which students it admits, meaning anyone can receive an education there.
Typically, they are run by the local education authority, which is part of the local council that specific area.
The Cambridge Dictionary defines a comprehensive school as: "A school in the UK for children of all abilities above the age of eleven, that is paid for by the state."
Other types of schools that children can attend include: private schools, faith schools, grammar schools, academies and independent schools.
Most other types of schools require funding from other means, such as fees.
Many private schools have a charitable status, which means they are entitled to claim tax breaks.
Across the UK schools are arranged in a devolved system, which means that authorities in England, Scotland, Wales and Northern Ireland are free to determine how schools are operated.
Want a quick and expert briefing on the biggest news stories? Listen to our latest podcasts to find out What You Need To Know.