According to People magazine, a representative for Richie announced the news of the end of their relationship. The star also declared that they were never really a couple.
The young woman, who stars in the TV show Simple Life, and Jenner have known each other since they were children. They began dating in August.
Before Nicole, Jenner had been dating actress Kristin Cavallari, and Richie had been engaged to DJ AM Goldstein.
Richie, 25, wrote on her MySpace site, "The truth is, we were never really together. We hung out, and he’s a nice guy, but my heart was never in it. Anything further is just a cry for publicity."