Lalita Gupta is Rajesh Koothrappali's childhood acquaintance. Her only appearance was in Season 1's "The Grasshopper Experiment". She went on a date with Raj, but it went terribly as a Raj got drunk so he could speak to her, and acted obnoxious. She eventually ditched Raj for Sheldon, who said she looked like a princess from a children's story he liked, which Lalita mistook for flirting. At the end of the night, they departed (because Sheldon already had a dentist) and she is never heard from again.
Lalita is in her mid-twenties and grew up in the same neighborhood as Raj. As a child, she used to bully Raj by kicking him in the groin, or "samosas" as according to Raj, and calling him an "untouchable". However, as adults, it turned out that their parents had arranged their marriage, the main reason being Raj's mother thought that he should be married at his age and that she and his father wanted grandchildren. As it turned out, just like Raj, she is also in America, to be a dental student at the University of Southern California. Raj detested this as he remembered clearly his experience being bullied by her, calling her pushy. She is also known as "Little Lalita", and her father plays golf alongside Raj's father.
She used to be fat as a kid but has slimmed down and became attractive as an adult. Sheldon felt that she resembled Princess Panchali from the children's story The Monkey and The Princess, which his mother read to him as a kid whenever he was sick.