Ai2 has released OLMo 2, a new family of fully open-source language models that significantly advances the field of AI. Available in 7B and 13B parameter versions, these models demonstrate performance competitive with or surpassing other open-source and proprietary models. Trained on up to 5 trillion tokens, OLMo 2 incorporates innovative techniques in training stability, staged learning, and post-training methodologies. The release includes comprehensive documentation, evaluation frameworks, and instruct-tuned variants, setting a new standard for transparency and accessibility in AI development. This breakthrough narrows the gap between open and proprietary AI systems, potentially accelerating innovation in the field.