Radian 3QX › fit in › Toyota Grand Highlander
Will the Diono Radian 3QX fit in a 2024–2024 Toyota Grand Highlander?
Yes — the Diono Radian 3QX fits a 2024–2024 Toyota Grand Highlander.
The Radian 3QX is about 17" wide; the Grand Highlander's usable rear bench is about 54". It fits one rear position comfortably. Three even fit across the back (51" needed vs 54").
The Radian 3QX is about 17" wide; the Grand Highlander's usable rear bench is about 54". It fits one rear position comfortably. Three even fit across the back (51" needed vs 54").
17"Radian 3QX width
54"Grand Highlander rear bench
Yesthree across
★★★☆☆NHTSA Ease-of-Use
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What fits this Grand Highlander
- One seat, rear position: Yes. The Radian 3QX installs in an outboard rear position of a 2024–2024 Toyota Grand Highlander with room to spare.
- Three across: Yes — three need ~51" against a ~54" 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 Grand Highlander has 3 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 Grand Highlander's rear-bench width (Typical for 3-row suv — approximate, verify install in your vehicle) are both approximate — confirm with a test-fit before buying.
Common questions
Will the Diono Radian 3QX fit in a 2024–2024 Toyota Grand Highlander?
Yes — the Diono Radian 3QX (17" wide) fits a single rear seating position in a 2024–2024 Toyota Grand Highlander. Three of them also fit across its roughly 54" rear bench.
Can you fit three Radian 3QXs across a Grand Highlander?
Yes — three Radian 3QXs need about 51" and the Grand Highlander's usable bench is about 54". It's close, so test-fit before buying.
Sources: seat ratings & modes — NHTSA (pulled 2026-06-18); 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.