9:46 AM PT -- Conor McGregor tells TMZ Sports ... he is planning to appeal Friday's decision.

In a statement, the UFC superstar said, "The judge's instruction and the modest award given was for assault, there was not an award for aggravated or exemplary damages. I am disappointed that the jury did not hear all the evidence that the DPP reviewed."

He added, "I am with my family, focused on my future."

Conor McGregor has lost his civil rape case in Ireland ... a jury just found him liable for assault.

The case had been going on all month long -- after Nikita Ni Lamhain claimed McGregor and another man had sex with her against her will after a 2018 Christmas party.

Ni Lamhain -- also known as Nikita Hand -- alleged the UFC superstar picked her and her friend up following the holiday get-together ... and took them to a nearby hotel. She claimed while there, McGregor forced himself on her on a bed in a penthouse suite. She also stated that later, another man, James Lawrence, sexually assaulted her too.

McGregor and Lawrence had adamantly denied the allegations ... with the 36-year-old fighter claiming their encounter was entirely consensual.

The jurors in the case clearly didn't believe McGregor's side of the story, however ... and awarded Ni Lamhain roughly $250,000 in damages. In their ruling, they did state they found that Lawrence did NOT assault the woman.

McGregor -- who showed up to Friday's proceedings with his longtime partner, Dee Devlin, by his side -- was in the courtroom as the verdict was announced.

He was swarmed by media members after he left the courthouse ... but he did not make a public comment.