The 38-year-old filed legal documents this week in London's High Court, accusing Noel of lying when he claimed that the band pulled out of their 2009 V Festival slot because Liam "had a hangover".
Liam had claimed that Noel's version of events was "breaking his heart", as he feels that he was not responsible for Oasis's demise later that year.
While Liam initially demanded an apology from Noel, he decided to take legal action when his brother failed to respond, insisting that there was no truth to Noel's claims about his drinking as well as an apparent dispute over advertising revenue for his clothing line Pretty Green.
"That is a lie and I want Oasis fans to know the truth," Liam told The Sun in reference to the drinking accusations. "I was gutted when I couldn't play the gig because I didn't want to let the fans down. The truth is I had laryngitis, diagnosed by a doctor, preventing me performing that night."
He added: "There are many reasons why Oasis split. But it had nothing to do with my clothing range."
A source told the publication: "Liam felt he had no choice but the courts. He feels a mix of anger at how he has been treated by his own elder brother and sadness [that] it has come to this."
Noel recently admitted that leaving Oasis was a "hasty" decision that he now regrets as he had high hopes for the band's future.
Watch the video to 'Don't Look Back In Anger' by Oasis below: