Kia Optima vs Mazda Mazda6
Head-to-head reliability comparison from 13,056real NHTSA consumer complaints. Year-by-year breakdown, shared problems, crash & fire rates.
Which is more reliable, Kia Optima or Mazda Mazda6?
Verdict from 13,056 NHTSA complaints
Mazda Mazda6 wins this comparison overall. Mazda Mazda6 comes out ahead on 2 of 4 reliability metrics — including a 30% lower complaint rate. The Kia Optima edges ahead on crash-involvement rate and overall severity score.
Head-to-Head Metrics
Lower is better on every metric. Bar length = relative magnitude. ✓ = winner.
Mazda Mazda6 wins by 30%
Kia Optima wins by 35%
Mazda Mazda6 wins by 369%
Kia Optima wins by 1688%
NHTSA Crash Test Ratings
Official NCAP star ratings — government crash test data. Most recent rated model year.
Kia Optima
2020 model yearMazda Mazda6
2021 model yearSource: NHTSA New Car Assessment Program (NCAP). Lower star = higher injury risk in that crash type.
Complaint Volume — Year by Year
Sales-volume data not available for both models — showing raw complaint counts. Higher-volume models will appear higher even when reliability is comparable.
Most Reported Problems
Top component complaints for each model. Identical bar lengths = both have the same recurring issue.
Year-by-Year Head-to-Head
Lower is better. Click either model column to see that year's full breakdown.
| Year | Kia Optima | Mazda Mazda6 | Better |
|---|---|---|---|
| 2002 | 168 | 40 | Mazda6 |
| 2003 | 190 | 245 | Optima |
| 2004 | 306 | 196 | Mazda6 |
| 2005 | 180 | 180 | tie |
| 2006 | 214 | 207 | tie |
| 2007 | 217 | 184 | Mazda6 |
| 2008 | 188 | 121 | Mazda6 |
| 2009 | 166 | 526 | Optima |
| 2010 | 99 | 317 | Optima |
| 2011 | 768 | 183 | Mazda6 |
| 2012 | 1,243 | 128 | Mazda6 |
| 2013 | 1,851 | 34 | Mazda6 |
| 2014 | 769 | 196 | Mazda6 |
| 2015 | 1,372 | 78 | Mazda6 |
| 2016 | 1,036 | 107 | Mazda6 |
| 2017 | 341 | 73 | Mazda6 |
| 2018 | 321 | 72 | Mazda6 |
| 2019 | 297 | 5 | Mazda6 |
| 2020 | 185 | 3 | Mazda6 |
Frequently Asked Questions
Kia Optima vs Mazda Mazda6 — the most common buyer questions, answered from NHTSA data.
Which is more reliable, the Kia Optima or the Mazda Mazda6?
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Mazda Mazda6 wins this comparison overall. Mazda Mazda6 comes out ahead on 2 of 4 reliability metrics — including a 30% lower complaint rate. The Kia Optima edges ahead on crash-involvement rate and overall severity score. Source: NHTSA Office of Defects Investigation via VinItel.
Should I buy a Kia Optima or a Mazda Mazda6?
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On reliability data alone, the Mazda Mazda6 is the safer bet — but the actual condition of the specific car matters far more than the model average. Check the VIN of any vehicle you're considering for accident history, title issues, and odometer rollbacks.
What problems do the Kia Optima and Mazda Mazda6 share?
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Top complaints for the Kia Optima: Engine Problems, Electrical Faults, Steering Defects. Top complaints for the Mazda Mazda6: Airbags, Suspension Failures, Electrical Faults. Source: NHTSA via VinItel.
Which has fewer NHTSA complaints, the Kia Optima or the Mazda Mazda6?
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Across all model years, the Kia Optima has 10,142 NHTSA complaints and the Mazda Mazda6 has 2,914. Normalized for sales volume (complaints per 10,000 vehicles sold), the Kia Optima has the lower complaint rate. Raw counts can mislead — a 2× more popular model will naturally collect 2× more complaints. Detailed normalized comparison: vinitel.com/stats/nhtsa-complaints/compare/kia/optima/vs/mazda/mazda6
Which is safer in a crash, the Kia Optima or the Mazda Mazda6?
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Crash-involvement rate from NHTSA complaints: Kia Optima 4.9% vs Mazda Mazda6 6.6% — the Kia Optima has the lower crash rate. NHTSA NCAP star ratings (frontal, side, rollover) for both models are also shown on the comparison page. Note: the per-VIN history matters more than the model average — a salvage-title car of any model carries higher crash exposure than the median.
Does the Kia Optima or the Mazda Mazda6 have more fires?
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Fire-involvement rate based on NHTSA complaints: Kia Optima 6.10% vs Mazda Mazda6 1.30%. The Mazda Mazda6 has the lower reported fire rate. Fire complaints are a relatively rare but important safety signal — they often correlate with electrical-system or fuel-system defects. Check specific recall campaigns at vinitel.com/stats/nhtsa-complaints/kia/optima and vinitel.com/stats/nhtsa-complaints/mazda/mazda6
What years of the Kia Optima are worse than the Mazda Mazda6?
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The comparison page renders a year-by-year head-to-head table — for each model year (where both models have data), it shows complaint count or per-10K rate side by side and marks which model fares better that year. Buyers cross-shopping a specific model year should always check the year-level VinItel pages: vinitel.com/stats/nhtsa-complaints/kia/optima/{year} and vinitel.com/stats/nhtsa-complaints/mazda/mazda6/{year}.
Where does this Kia Optima vs Mazda Mazda6 comparison data come from?
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All complaint, crash, fire, and fatality data comes from the NHTSA Office of Defects Investigation (ODI) consumer-complaint database — the same source insurance regulators and the federal government use. NCAP star ratings come from NHTSA's New Car Assessment Program crash tests. Sales-volume normalization (per 10K sold) uses US annual vehicle sales. Data refreshes every 6 hours. Source: NHTSA via VinItel.
Related Reliability Comparisons
Other head-to-head matchups buyers cross-shopping the Optima or Mazda6 also look at:
Comparison data refreshed 2026-05-04 from NHTSA Office of Defects Investigation.·Source: NHTSA ODI
A model average can't see the car you're buying.
Even the Mazda Mazda6 has cars with hidden accidents, salvage titles, and odometer rollbacks. Check the VIN before you buy — full report $4.99 (vs. Carfax $44.99).
Deep-dive into either model: