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Gemini 1.5 Pro vs GPT-5.3-Codex

Google Gemini 1.5 Pro vs OpenAI GPT-5.3-Codex — side-by-side specs.

Google
Gemini 1.5 Pro
OpenAI
GPT-5.3-Codex
Overview
CompanyGoogleOpenAI
Release dateFeb 15 2024Feb 5 2026
Model type
Open sourceNoNo
Specifications
Parameters
Context window
Benchmarks
Timeline
Release gapGemini 1.5 Pro shipped 721 days before GPT-5.3-Codex

Which is better: Gemini 1.5 Pro or GPT-5.3-Codex?

Gemini 1.5 Pro and GPT-5.3-Codex don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. Gemini 1.5 Pro shipped 721 days before GPT-5.3-Codex, so benchmark comparisons should account for the intervening progress.

Published specifications for these two models are limited — see each model page for the latest details.

Direct benchmark comparisons are unavailable — Gemini 1.5 Pro and GPT-5.3-Codex don't publish scores on any of the same benchmarks.

Frequently asked questions

When was Gemini 1.5 Pro released?
Gemini 1.5 Pro was released by Google on Feb 15 2024.
When was GPT-5.3-Codex released?
GPT-5.3-Codex was released by OpenAI on Feb 5 2026.

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