Ms Cooper gained 18,832 votes, increasing her majority from 3,244 to 6,373.
Conservative candidate Paul White came second with 12,479 votes.
Burnley's Liberal Democrat stalwart Gordon Birtwistle lost out for a second time, after being defeated by Ms Cooper in 2015. He gained 6,046 votes. The turnout was 62.3%.
Ms Cooper said: "I'm absolutely thrilled and hugely honoured. My majority has increased twofold. That is amazing.
"Hopefully I've proved to [the people of Burnley] I'm committed to standing up for them and being a strong voice for them in Westminster... I also know that people have liked the Labour manifesto, a strong and powerful manifesto, and people have wanted to back that."
The Conservatives failed to gain its target seats of Blackpool South, Lancaster and Fleetwood, Hyndburn or Chorley. They were all held by Labour.
Labour targeted seats in Blackpool North and Cleveleys, Pendle, South Ribble, Rossendale and Darwen and Morecambe and Lunesdale but the Conservatives held these seats.
In Lancashire, not a single seat has changed hands following the 2015 election result.
A hung parliament is going to make Brexit extremely difficult, the Conservative MP for Fylde said.
"If we've a coalition of chaos the ability to deliver Brexit will be nigh on impossible," Mark Menzies said.
Ribble Valley Conservative MP Nigel Evans, lamenting his party's overall performance in the general election, said: "A number of senior Tories lost their seats...it's a tragedy you can put down to our manifesto."
Graham Jones, who was elected MP for Hyndburn with an increased majority of 5,815, said: "I never get complacent but do appreciate the fact that I've won for a third term and I thank the people of Haslingden and Hyndburn for electing me.
"My promise is a simple promise, I'll work hard."
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Labour's Julie Cooper has held her seat in Burnley, the Liberal Democrats' top target in the North West.