Model Comparison

Gemini 2.0 Flash Thinking vs GPT-5.6 LunaWhich is better in 2026?

GPT-5.6 Luna significantly outperforms across most benchmarks.

Verdict: Gemini 2.0 Flash Thinking vs GPT-5.6 Luna — which is better?

Gemini 2.0 Flash Thinking (by Google) and GPT-5.6 Luna (by OpenAI) are two of the AI models people compare most. Here is how they stack up on benchmarks, price and capabilities, and which one to pick in 2026.

Gemini 2.0 Flash Thinking outperforms in 0 benchmarks, while GPT-5.6 Luna is better at 1 benchmark (GPQA). GPT-5.6 Luna significantly outperforms across most benchmarks.

Choose Gemini 2.0 Flash Thinking if…

  • you are already invested in the Google ecosystem

Choose GPT-5.6 Luna if…

  • you want the strongest raw capability — it leads on 1 of 1 shared benchmarks
  • you want the most recent training data — it shipped Jul 2026

Performance Benchmarks

Comparative analysis across standard metrics

1 benchmarks

Gemini 2.0 Flash Thinking outperforms in 0 benchmarks, while GPT-5.6 Luna is better at 1 benchmark (GPQA).

GPT-5.6 Luna significantly outperforms across most benchmarks.

Sat Jul 18 2026 • llm-stats.com

Arena Performance

Human preference votes

Context Window

Maximum input and output token capacity

Only GPT-5.6 Luna specifies input context (1,050,000 tokens). Only GPT-5.6 Luna specifies output context (128,000 tokens).

Google
Gemini 2.0 Flash Thinking
Input- tokens
Output- tokens
OpenAI
GPT-5.6 Luna
Input1,050,000 tokens
Output128,000 tokens
Sat Jul 18 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both Gemini 2.0 Flash Thinking and GPT-5.6 Luna support multimodal inputs.

They are both capable of processing various types of data, offering versatility in application.

Gemini 2.0 Flash Thinking

Text
Images
Audio
Video

GPT-5.6 Luna

Text
Images
Audio
Video

License

Usage and distribution terms

Both models are licensed under proprietary licenses.

Both models have usage restrictions defined by their respective organizations.

Gemini 2.0 Flash Thinking

Proprietary

Closed source

GPT-5.6 Luna

Proprietary

Closed source

Release Timeline

When each model was launched

Gemini 2.0 Flash Thinking was released on 2025-01-21, while GPT-5.6 Luna was released on 2026-07-09.

GPT-5.6 Luna is 18 months newer than Gemini 2.0 Flash Thinking.

Gemini 2.0 Flash Thinking

Jan 21, 2025

1.5 years ago

GPT-5.6 Luna

Jul 9, 2026

1 weeks ago

1.5yr newer

Knowledge Cutoff

When training data ends

Gemini 2.0 Flash Thinking has a knowledge cutoff of 2024-08-01, while GPT-5.6 Luna has a cutoff of 2026-02-16.

GPT-5.6 Luna has more recent training data (up to 2026-02-16), making it potentially better informed about events through that date compared to Gemini 2.0 Flash Thinking (2024-08-01).

Gemini 2.0 Flash Thinking

Aug 2024

GPT-5.6 Luna

Feb 2026

1.5 yr newer

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

Google

No standout differentiators in the data we have for this pair.

OpenAI
Larger context window (1,050,000 tokens)
Higher GPQA score (92.3% vs 74.2%)

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against Gemini 2.0 Flash Thinking and GPT-5.6 Luna side-by-side, then vote on the output you prefer.

Gemini 2.0 Flash Thinking
✓ Preferred
GPT-5.6 Luna
Open in Playground
AI Model Comparison Table
Feature
Google
Gemini 2.0 Flash Thinking
OpenAI
GPT-5.6 Luna

FAQ

Common questions about Gemini 2.0 Flash Thinking vs GPT-5.6 Luna.

Which is better, Gemini 2.0 Flash Thinking or GPT-5.6 Luna?

GPT-5.6 Luna significantly outperforms across most benchmarks. Gemini 2.0 Flash Thinking is made by Google and GPT-5.6 Luna is made by OpenAI. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does Gemini 2.0 Flash Thinking compare to GPT-5.6 Luna in benchmarks?

Gemini 2.0 Flash Thinking scores MMMU: 75.4%, GPQA: 74.2%, AIME 2024: 73.3%. GPT-5.6 Luna scores Connectors: 99.9%, HealthBench Consensus: 95.1%, GPQA: 92.3%, Search and Function-Calling: 89.7%, Capture-the-Flag Challenges (Internal): 85.2%.

What are the context window sizes for Gemini 2.0 Flash Thinking and GPT-5.6 Luna?

Gemini 2.0 Flash Thinking supports an unknown number of tokens and GPT-5.6 Luna supports 1.1M tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

Who makes Gemini 2.0 Flash Thinking and GPT-5.6 Luna?

Gemini 2.0 Flash Thinking is developed by Google and GPT-5.6 Luna is developed by OpenAI.

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