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 most answers say — 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
Every source is graded on the six-tier rubric and archived, so the citation holds even if the original moves or paywalls. The tier badge grades the source; the status grades our confidence in the maker.
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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