GPT-5.4 (Generative Pre-trained Transformer 5.4) is a large language model (LLM) released by OpenAI on March 5, 2026.
OpenAI released the model in two primary variants: GPT-5.4 Thinking and GPT-5.4 Pro. Neither is available to free-tier users.
In technical benchmarks, OpenAI reported a 33% reduction in factual errors compared to GPT-5.2. Performance improvements were focused on professional workflows.