The 27-year-old former heptathlete and long jumper produced a mark of 14.98 metres to see off Caterine Ibarguen of Colombia and Ukraine's world and double European champion Olha Saladuha who took silver and bronze respectively.
Rypakova, who won silver at last year's world championships, set the winning mark with her third attempt, finishing the night 18 centimetres clear of Ibarguen. Rypakova's previous season's best was 14.84.
Ukraine's Saladuha, a strong favourite to take gold in London having produced four of the top 10 best jumps this year, looked to have catapulted herself into the medal places with her last jump of 14.79 that put her second.
But it was not to be as Ibarguen, who had occupied the silver medal position for most of the night, went one centimetre better to reclaim second and push Saladuha into bronze.
All three medallists finished on the podium at last year's world championships in Daegu, South Korea.
Russia's Tatyana Lebedeva, who has two silver and one bronze Olympic medals, finished 10th and announced shortly after that she would retire, while Britain's oldest female Olympic track and field debutant Yamile Aldama, who turns 40 this month, ended fifth.
Aldama, who is in her fourth Games after competing for both Cuba and Sudan previously, couldn’t reproduce her season’s best of 14.82m, which would have been good enough for silver. Her sixth round jump of 14.48 metres was only good enough for fifth place.
Meanwhile, Robbie Grabarz secured himself a place in the Olympic high jump final with a solid jump of 2.29m to top his qualification group.
The 24-year-old Newham and Essex Beagles’ athlete, who became the first British high jumper to win the European title since 1950 in Helsinki earlier this year, will hope to put himself in the medal shake-up on Tuesday.
Alex Smith finished in 12th in the hammer final as Hungarian Krisztian Pars won with a 80.59m throw.
The Sale Harrier could only manage 72.87m in the second round but will have been delighted to have made it into the final in his debut Games .
"It was such a tough selection process with so much pressure that when I got here I didn't really feel any pressure," said Smith.
"I wasn't overwhelmed out there and while it was a goal to make the final, I didn't really expect to.
"I would have liked to have finished a few places higher, if I'd thrown what I did in qualifying I would have been in the top ten, which would have been a nice thing to say.
"My coach said I looked like I belong here, which is really nice. This does so much for my motivation.
“I want to go back to training, have a good and injury free winter and start working towards the World Championships in Moscow next year."