In an open letter to her fans on her MySpace.com blog, Lavigne said she has "never ripped anyone off," NME.com reported Monday.
The suit was filed last week against Lavigne by the 1970s group the Rubinoos, who said the rock artist copied lyrics of their "I Wanna Be Your Boyfriend."
"They claim that a small part of the lyrics are the same and are saying that I took these from them," Lavigne wrote. "I had never heard this song in my life ... . All songs share similar lyrics and emotions. As humans we speak one language."
In a related matter, Lavigne said she and songwriter Chantal Kreviazuk no longer would work together. Kreviazuk earlier said she would not work with Lavigne, suggesting the singer had ripped off her song.
Lavigne said she wrote a song with Evan Taubenfeld that happened to have the same title as a song Kreviazuk sent several years ago. Lavigne said the two songs have no similarities.
Lavigne said she stopped working with Kreviazuk because "we had no hits together."