# GPT-5.3 Codex vs Qwen3.5-27B

> Side-by-side benchmark comparison for GPT-5.3 Codex and Qwen3.5-27B across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/gpt-5-3-codex-vs-qwen3-5-27b
- Last updated: September 28, 2026

- Shared sourced benchmarks: 5
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.7

## Quick Verdict

Pick GPT-5.3 Codex if you want the stronger benchmark profile. Qwen3.5-27B only makes more sense when its price, context window, or workload-specific category wins matter more than the overall score.

## Summary

- GPT-5.3 Codex leads overall 62.06 to 43.76.
- The clearest category separation is in reasoning, where the averages are 79.6 for GPT-5.3 Codex and 52.7 for Qwen3.5-27B.
- The biggest single benchmark swing is Terminal-Bench 2.0 in Agentic, with scores of 77.3% and 41.6%.
- Qwen3.5-27B is the cheaper option on output tokens, which matters if you expect large responses or heavy interactive use.
- GPT-5.3 Codex also has the larger context window at 400K.

## Model Snapshot

| Property | GPT-5.3 Codex | Qwen3.5-27B |
|----------|----------|----------|
| Creator | OpenAI | Alibaba |
| Type | Proprietary | Open Weight |
| Reasoning | Reasoning | Reasoning |
| Context | 400K | 262K |
| Overall Score | 62.06 | 43.76 |
| Benchmarks Covered | 10 | 16 |
| Pricing (input/output) | $1.75 / $14.00 | $0.00 / $0.00 |

## Category Breakdown

### Agentic

- Winner: Directional only
- GPT-5.3 Codex public-lane score: 54.2 (Estimated · #35/117)
- Qwen3.5-27B public-lane score: 32.5 (Estimated · #74/117)

| Benchmark | GPT-5.3 Codex | Qwen3.5-27B | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.0 | 77.3% | 41.6% | GPT-5.3 Codex |
| OSWorld-Verified | 64.7% | 56.2% | GPT-5.3 Codex |
| Gert Labs | 57.47% | 39.41% | GPT-5.3 Codex |
| JobBench | 33.7% | Coming soon | Coming soon |
| BrowseComp | Coming soon | 61% | Coming soon |

### Coding

- Winner: Directional only
- GPT-5.3 Codex public-lane score: 55.4 (Supported · #28/142)
- Qwen3.5-27B public-lane score: 32.4 (Estimated · #86/142)

| Benchmark | GPT-5.3 Codex | Qwen3.5-27B | Winner |
|-----------|-----------|-----------|--------|
| SWE-bench Verified | 85% | 72.4% | GPT-5.3 Codex |
| SWE-bench Pro | 56.8% | Coming soon | Coming soon |
| SWE-Rebench | 58.2% | 58.9% | Qwen3.5-27B |
| Vibe Code Bench | 61.77% | Coming soon | Coming soon |
| LiveCodeBench (Vals) | 87.3% | Coming soon | Coming soon |
| SWE-bench (Vals) | 78.0% | Coming soon | Coming soon |

### Reasoning

- Winner: Not comparable
- GPT-5.3 Codex public-lane score: 79.6 (Unranked · 2 rankable rows)
- Qwen3.5-27B public-lane score: 52.7 (Unranked · 3 rankable rows)

| Benchmark | GPT-5.3 Codex | Qwen3.5-27B | Winner |
|-----------|-----------|-----------|--------|
| LongBench v2 | Coming soon | 60.6% | Coming soon |

### Multimodal & Grounded

- Winner: Not comparable
- GPT-5.3 Codex public-lane score: 76.7 (Unranked · 1 rankable row)
- Qwen3.5-27B public-lane score: 71.6 (Unranked · 3 rankable rows)

| Benchmark | GPT-5.3 Codex | Qwen3.5-27B | Winner |
|-----------|-----------|-----------|--------|
| MMMU | Coming soon | 82.3% | Coming soon |
| MMVU | Coming soon | 73.3% | Coming soon |
| MathVision | Coming soon | 86.0% | Coming soon |
| V* | Coming soon | 93.7% | Coming soon |

### Knowledge

- Winner: Directional only
- GPT-5.3 Codex public-lane score: 64.2 (Estimated · #29/168)
- Qwen3.5-27B public-lane score: 42.3 (Supported · #87/168)

| Benchmark | GPT-5.3 Codex | Qwen3.5-27B | Winner |
|-----------|-----------|-----------|--------|
| MMLU-Pro | Coming soon | 86.1% | Coming soon |
| SuperGPQA | Coming soon | 65.6% | Coming soon |
| GPQA | Coming soon | 85.5% | Coming soon |

### Multilingual

- Winner: Not comparable
- GPT-5.3 Codex public-lane score: Coming soon
- Qwen3.5-27B public-lane score: 36.8 (#9/12)

| Benchmark | GPT-5.3 Codex | Qwen3.5-27B | Winner |
|-----------|-----------|-----------|--------|
| MMLU-ProX | Coming soon | 82.2% | Coming soon |

### Instruction Following

- Winner: Directional only
- GPT-5.3 Codex public-lane score: 91.2 (#14/124)
- Qwen3.5-27B public-lane score: 91.5 (#13/124)

| Benchmark | GPT-5.3 Codex | Qwen3.5-27B | Winner |
|-----------|-----------|-----------|--------|
| IFEval | Coming soon | 95% | Coming soon |

## FAQ

### Which is better overall, GPT-5.3 Codex or Qwen3.5-27B?

GPT-5.3 Codex is ahead overall on BenchLM right now.

### Where is the biggest gap between GPT-5.3 Codex and Qwen3.5-27B?

The widest category gap is in reasoning, where the averages are 79.6 for GPT-5.3 Codex and 52.7 for Qwen3.5-27B.

### How many benchmarks does GPT-5.3 Codex cover on BenchLM?

GPT-5.3 Codex currently has 10 sourced benchmark scores on BenchLM.

### How many benchmarks does Qwen3.5-27B cover on BenchLM?

Qwen3.5-27B currently has 16 sourced benchmark scores on BenchLM.

## Related Comparisons

- [GPT-5.3 Codex vs GPT-5.3-Codex-Spark](/compare/gpt-5-3-codex-vs-gpt-5-3-codex-spark)
- [Qwen3.5-27B vs GPT-5.3-Codex-Spark](/compare/gpt-5-3-codex-spark-vs-qwen3-5-27b)
- [GPT-5.3 Codex vs GPT-6 Astra](/compare/gpt-5-3-codex-vs-gpt-6-astra)
- [Qwen3.5-27B vs GPT-6 Astra](/compare/gpt-6-astra-vs-qwen3-5-27b)

## Explore More

- [GPT-5.3 Codex profile](/models/gpt-5-3-codex)
- [Qwen3.5-27B profile](/models/qwen3-5-27b)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)