Who makes Kirkland Signature Organic Non-Dairy Oat Beverage (32 oz, 6-count)?
As of July 5, 2026, evidence points to SunOpta Inc. as the manufacturer of Kirkland Signature Organic Non-Dairy Oat Beverage (32 oz, 6-count), but no tier 1–3 source names the link directly.
The common claim
What’s commonly claimed, and what the evidence supports
The prevailing answer is SunOpta, and the evidence points that way but only indirectly: the Star Tribune reported in 2023 that SunOpta 'makes most of its money manufacturing product for store brands and private label (like Costco's Kirkland Signature),' naming Kirkland Signature as a SunOpta private-label customer. That statement sits in an article about SunOpta's plant-based milks generally rather than the Kirkland oat beverage specifically, and no Costco or SunOpta statement singles out the oat SKU, so the attribution is probable, not confirmed. Product reviews of the Kirkland oat beverage do not disclose a maker, and its carton carries only distributed-by-Costco labeling.
Evidence & sources
Each source is graded on the six-tier evidence rubric, where tier 1 is strongest. Sources are archived, so a citation still works if the original page moves or goes behind a paywall.
Tier 4
Business-press naming of the SunOpta–Kirkland link: 'SunOpta, a leading plant-based milk maker, makes most of its money manufacturing product for store brands and private label (like Costco's Kirkland Signature). In-house brands - like Dream and West Life - represents less than 10% of its roughly $900 million in annual sales.' Graded indirect (probable, not confirmed): the naming is a parenthetical example inside a general statement, in an article about SunOpta's plant-based milks broadly (oat, soy, almond) rather than the Kirkland oat SKU specifically, and neither Costco nor SunOpta is quoted confirming the oat beverage.
Tier 6
Industry-context corroboration (does NOT name Kirkland): SunOpta's own oat-beverage page describes its private-label oat manufacturing: 'We start with North American whole rolled oats to create our proprietary gluten-free oatbase,' offered in aseptic packaging with 'custom formulations, certifications and sourcing' for customers. Establishes SunOpta as a private-label / co-manufacturer of oat milk, which makes the Star Tribune attribution plausible; it is context, not the anchor.
Frequently asked
Who makes Kirkland Signature organic oat beverage?
Is Kirkland oat milk the same as Oatly?
How could the SunOpta attribution be confirmed or overturned?
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