Lola Montgomery is the illegitimate child of Meredith Gates and Byron Montgomery.

Meredith found out that she was pregnant during the novel "Unbelievable". During her pregnancy, Meredith focused on eating healthy, and invested in a variety of tips and guidelines for a good pregnancy and birthing process. Meredith went into labor and delivered a healthy baby at the end of "Wanted". After giving birth to the baby girl, Meredith asks Aria for help in naming the baby, whom she names Lola.

Throughout the books following "Wanted", Aria is seen frequently babysitting her younger half-sister which often interferes with her own personal life. For instance, Aria was unable to go away skiing with her boyfriend Noel because she had already promised her father and Meredith that she would watch Lola. 

Author Sara Shepard describes Lola a lot like Aria, meaning that they have a similar facial structure and they both have dark brown hair.