Kipyegon controlled the field and knocked almost five seconds off the world mark as she finished nearly seven seconds ahead of second-placed Ciara Mageean from Ireland.
Kipyegon completed the race in four minutes, 7.64 seconds to smash Dutchwoman Sifan Hassan's 2019 mark of 4:12.33.
Hassan's record was also set in Monaco.
"I have done good training so far and I just came for it. The time - yes, it was really good because the race was well planned. It just went smoothly and to accomplish the world record - that is amazing," Kipyegon, who took the lead with two laps to run, said.
Kipyegon, who was embraced by her fellow competitors after the race, has now broken three world records in just two months, including the 1500m and 5000m.
"I do not know how I am doing this because it just keeps going really in a good way," the Kenyan added.
"When I started this season, my goal was to just break the 1500m world record. It was still in my head and in my mind. Thank God I did also the one mile and the 5000m. So many.
"I want to defend my world title at 1500m in Hungary but I am going to double also with 5000m in Budapest."
In a race where many of the competitors achieved personal best times, Ireland's Mageean set a new national record. Ethiopian Freweyni Hailu claimed bronze after finishing ahead of Britain's Laura Muir.
"I think it's been my best season yet. I have opened it strong and have stayed consistent," Mageean said.
"Today I ran an Irish record over the mile. I am really proud of myself for that. I feel I am in a really good place to go the World Championships.
"Sometimes when you know you are in a good shape, it's a bit more scary because you really know that you can achieve your goals."
Omanyala ran the men's 100m in 9.92, one tenth of a second ahead of Letsile Tebogo of Botswana while Jamaica's Ackeem Blake took third place.
"Tonight, I just confirmed what I am capable of," Omanyala said after securing his first Diamond League victory in the 100m.
"I wanted a faster time but win is a win."
American Fred Kerley, who suffered his first defeat of the season last week at the Silesia Diamond League, did not run.
Norwegian Karsten Warholm posted his second-best ever time in the 400m hurdles, clocking 46.51, a tenth of a second faster than his own Diamond League record set in Oslo last month.
Alison Dos Santos from Brazil made a valiant effort to keep pace but Warholm had a firm hold on the race from the start, sending a warning shot to his rivals ahead of the World Athletics Championships in Budapest next month.
"This is nice timing as the World Championships are just around the corner," Warholm said.
"Seeing that things are still working and I can go faster and faster every time, that means a lot."
Jamaica's Shericka Jackson scorched to victory in the 200m with 21.86, ahead of Julien Alfred from Saint Lucia.
"Oh, my execution, I do not think that the curve was as good as I wanted but I managed to go until the finish so it was good," Jackson said.
Britain's former world champion Dina Asher-Smith took third place with a time of 22.23, her season's best.
Sweden's world record holder, Armand Duplantis, experienced a challenging time at the pole vault competition, losing the event for the first time this year.
He failed to clear the winning height of 5.92m set by American Christopher Nilsen and finished in fourth place.
"Today did not go as planned, and this is my last competition before the World Championships in Budapest. So, I will try to be careful, rest well, and work on my left side," Duplantis said.
"It was a bad day and I will be back in full shape in Budapest."
