LLM4Ranking is a unified framework designed to facilitate the utilization of large language models (LLMs) for document reranking in various applications, such as search engines. It offers a simple and extensible interface, along with evaluation and fine-tuning scripts, allowing users to experiment with different ranking methods and models on popular datasets. The framework aims to enhance the performance and efficiency of LLMs in document reranking tasks and is available as open-source code.