Milwaukee M18 and RYOBI 18V ONE+ batteries are not interchangeable. What surprises most shoppers is that the two brands are corporate siblings: both are owned by Techtronic Industries (TTI). TTI’s own Brands page lists both MILWAUKEE and RYOBI together, describing them as brands that “provide innovative solutions for the toughest outdoor projects.” That is a confirmed, official ownership fact straight from the parent company — not third-party speculation.
Still, common ownership is a balance-sheet detail, not a battery specification. Milwaukee and RYOBI operate as entirely separate power-tool platforms, and neither brand’s own product pages treat the other’s tools as part of its ecosystem.
Milwaukee makes its M18 scope explicit. The company’s Batteries and Chargers page states, “All M18 batteries are compatible with M18 tools and chargers” — a same-platform claim only. Its One-Key Resources guide, “How to Choose a Milwaukee Tool Battery,” doubles down: “M18 tools use M18 REDLITHIUM batteries rated at 18 volts,” and “Batteries are not interchangeable across power tool systems, but are interchangeable within them.” That wording is platform-wide, not brand-specific, but it is the rule Milwaukee applies to its own batteries: swap freely inside M18, do not expect to swap outside it.
RYOBI’s story is one of backward compatibility inside its own system. The brand’s 18V ONE+ collection page says its first cordless drill, a Ni-Cd model, debuted in 1996 and founded the ONE+ platform. Lithium-ion arrived in 2007 “while remaining fully compatible with the existing ONE+ platform,” and the system now includes “over 300+ compatible products” that RYOBI says are “compatible across products from the last 3 decades.” Again, that compatibility is internal to ONE+ — RYOBI does not say those three decades of products include Milwaukee M18 tools.
The real tell is what neither brand says. Milwaukee’s platform pages do not list RYOBI tools as M18-compatible. RYOBI’s ONE+ pages do not list Milwaukee tools as ONE+-compatible. And TTI’s corporate Brands page, the one place that openly names both brands together, makes no compatibility claim at all. If cross-brand battery use were intended, it would almost certainly appear somewhere in that official documentation; it does not.
So the practical takeaway is straightforward: yes, Milwaukee and RYOBI are sibling brands under Techtronic Industries — that’s a real, officially confirmed fact, not a rumor. But shared corporate ownership is a business structure, not a battery specification. Neither brand’s product pages state their batteries cross over, and TTI’s own brands page (which does mention both brands together) makes no compatibility claim either. Treat Milwaukee M18 and RYOBI ONE+ as two fully separate systems requiring separate batteries and chargers — the same rule this site has found holds true for every other same-parent-company pairing checked so far.
How this was checked
Facts on this page are drawn from Milwaukee’s own Batteries and Chargers page and “How to Choose a Milwaukee Tool Battery” guide, RYOBI’s own 18V ONE+ collection page, and Techtronic Industries’ own Brands page.
Sources checked: 2026-08-11. A new review date will only be set after the linked pages are re-checked.