Lorenzo lost the front end of his bike when he attempted to pass Maverick Vinales for third position on Turn 10.
His Honda Repsol slid directly into Dovizioso who was in second position and then into Vinales.
Rossi, who was too close behind, tried to avoid the pile up but also crashed out.
It is Rossi’s second race in a row that he has not finished.
It was a devastating blow for the three riders who were taken out, each losing potential championship points.
Dovizoso, who remains second in the championship, is now 37 points behind championship leader Marc Marquez, who is on 140 points.
Before race-start they shared a 12-point gap.
It was an important race for the Ducati rider Marquez who needed a podium finish to keep a firm hold on the championship.
The Catalunya GP saw an unusual number of MotoGP riders crash out.
Only 13 riders completed the race and 11 did not finish with Marquez breezing through a first place finish.
Lorenzo promptly apologised when approached by the media in his garage.
Fellow Spaniard Vinales was not happy, claiming that Lorenzo “didn’t come to the box to say sorry” on a personal level.
Vinales was not shy of calling out Lorenzo for destroying his race and for damaging Dovizioso’s run for the championship.
“He also took out Andrea [Dovizioso] who is fighting for the championship,” Vinales said.
“Today he destroyed my race, Valentino’s and Dovizioso’s championship.
“It’s pretty hard to recover 25 points.”
The Yamaha rider has requested FIM Stewards penalise Lorenzo for the “rookie mistake”, saying that he should start at the back of the grid for the next race in Assen.
Lorenzo explained that he was likely too excited and that a combination of factors led to the crash, including the turn.
“I was probably too excited, knowing that I was feeling good … I didn’t make any crazy braking,” he said.
“My opinion is that this hairpin corner creates these crashes and we’ve seen it many times.”
But Vinales was unrelenting, saying “honestly this corner is always difficult - but come on!”
Lorenzo said he went to both Ducati and Yamaha’s garages to apologise to the riders.
He successfully tracked down Dovizioso but said Yamaha riders Rossi and Maverick were not present when he entered their garage.
“Obviously the worst thing, more than my crash, is that I made the three crash,” Lorenzo admitted.
“Because they are fighting for the championship.
“I am not… I don’t have almost any points and it doesn’t matter if I crash.”
Marquez now leads the championship on 140 points, with Dovizioso in second on 103 points and Rins in third on 101 points.
Catch the Assen GP on Sunday, June 30, 2019, at 10:00 pm AEST.
Catalunya GP Results (Round 7)
- Marquez (SPA) - Repsol Honda
- Quartararo (FRA) - Petronas Yamaha
- Petrucci (ITA) - Ducati
- Rins (SPA) - Suzuki Ecstar
- Miller (AUS) - Pramac Ducati
- Mir (SPA) - Suzuki Ecstar
- Pol Espargaro (SPA) – Red Bull KTM Factory
- Nakagami (JPN) - LCR Honda
- Rabat (SPA) - Reale Avintia Ducati
- Zarco (FRA) - Red Bull KTM Factory
- Iannone (ITA) - Factory Aprilia Gresini
- Oliveira (POR) - Red Bull KTM Tech3
- Sylvain Guintoli (FRA) Suzuki Ecstar
DID NOT FINISH
Abraham (CZE) - Reale Avintia Ducati
Crutchlow (GBR) - LCR Honda
Bradley Smith (GBR) – Factory Aprilia Gresini
Dovizioso (ITA) – Ducati
Rossi (ITA) - Monster Yamaha
Bagnaia (ITA) - Pramac Ducati
Morbidelli (ITA) - Petronas Yamaha
Syahrin (MAL) - Red Bull KTM Tech3
Aleix Espargaro (SPA) Factory Aprilia Gresini
Lorenzo (SPA) - Repsol Honda
Vinales (SPA) - Monster Yamaha