Lonnie began as a pet form of Alonzo, the Spanish form of Alfonso, which comes from Germanic elements meaning "noble" and "ready"; it has also served as a nickname for Leonard. It was a popular American given name in the mid-20th century, with a friendly, down-home sound. Lonnie ranked number 826 in 2000, dropped out of the top 1000 soon after and stands at number 1843 in 2025, with 86 boys given the name.