Lineage · Since 2018
The GPT lineage
OpenAI's Generative Pre-trained Transformer family, from GPT-1 through GPT-5.
Generation 1 · Feb 14, 2019
GPT-2
Second-generation GPT model, initially released with a staged rollout over safety concerns.
Open1.0K ctxtext generation
Generation 2 · Jun 11, 2020
GPT-3
175B parameter model that established the modern LLM API paradigm.
Closed2.0K ctxfew-shot learningtext generation
Generation 3 · Nov 30, 2022
GPT-3.5
Instruction-tuned refresh of GPT-3 that powered the original ChatGPT launch.
Closed4.1K ctxinstruction followingchat
Generation 4 · Mar 14, 2023
GPT-4
Multimodal successor to GPT-3.5 with substantial gains on reasoning benchmarks.
Closed8.2K ctxMultimodalreasoningmultimodal
Generation 5 · May 13, 2024
GPT-4o
Omni-model unifying text, vision and audio in a single network with realtime capabilities.
Closed128K ctxMultimodalrealtime voicevision
Generation 6 · Aug 7, 2025
GPT-5
OpenAI's next-generation flagship model succeeding GPT-4o.
Closed400K ctxMultimodaladvanced reasoningcoding