Radian 3QX › fit in › Toyota Highlander
Will the Diono Radian 3QX fit in a 2020–2024 Toyota Highlander?
Yes — the Diono Radian 3QX fits a 2020–2024 Toyota Highlander.
The Radian 3QX is about 17" wide; the Highlander's usable rear bench is about 52". It fits one rear position comfortably. Three even fit across the back (51" needed vs 52").
The Radian 3QX is about 17" wide; the Highlander's usable rear bench is about 52". It fits one rear position comfortably. Three even fit across the back (51" needed vs 52").
17"Radian 3QX width
52"Highlander rear bench
Yesthree across
★★★☆☆NHTSA Ease-of-Use
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What fits this Highlander
- One seat, rear position: Yes. The Radian 3QX installs in an outboard rear position of a 2020–2024 Toyota Highlander with room to spare.
- Three across: Yes — three need ~51" against a ~52" bench. Test-fit; three-across is decided by half-inches.
- Modes this seat covers: rear-facing → forward-facing → booster.
- LATCH: lower anchors up to 40 lb; the Highlander has 2 lower-anchor positions.
ℹ️ Informational only — built from NHTSA public car-seat ratings and published seat/vehicle dimensions. This is not a safety certification and not a substitute for the seat and vehicle manuals. Always confirm the fit and install yourself before every trip. The Radian 3QX's width (Diono published spec (steel-framed, 17 in)) and the Highlander's rear-bench width (Toyota dimensions + owner measurements (approx)) are both approximate — confirm with a test-fit before buying.
Common questions
Will the Diono Radian 3QX fit in a 2020–2024 Toyota Highlander?
Yes — the Diono Radian 3QX (17" wide) fits a single rear seating position in a 2020–2024 Toyota Highlander. Three of them also fit across its roughly 52" rear bench.
Can you fit three Radian 3QXs across a Highlander?
Yes — three Radian 3QXs need about 51" and the Highlander's usable bench is about 52". It's close, so test-fit before buying.
Sources: seat ratings & modes — NHTSA (pulled 2026-06-17); dimensions — manufacturer specs and owner measurements. Informational only — built from NHTSA public car-seat ratings and published seat/vehicle dimensions. This is not a safety certification and not a substitute for the seat and vehicle manuals. Always confirm the fit and install yourself before every trip.