If past years are any indication, the event will be used to unveil a slew of new products, including new iPhones, a new Apple Watch, and maybe even a refreshed pair of its wireless AirPods.
Based on analysts, leaks, and reports, here's what we're expecting Apple to announce at its biggest hardware event of the year.
Apple is expected to unveil new smartphones with super-high definition OLED screens, potentially named the iPhone Xs and iPhone Xs Max ...
According to KGI Securities analyst Ming-Chi Kuo, Apple is expected to release three new iPhones total, including two devices with OLED screens.
The two OLED phones will come in different sizes -- 6.5-inch and 5.8-inch -- and will have the same nearly full-screen display and facial recognition camera as the iPhone X.
Last month, Apple blog 9to5Mac published what it said was an actual marketing photo for two new iPhone devices. The images show two gold phones, which 9to5Mac says are called the iPhone XS and the iPhone XS Max.
... along with a low-cost iPhone with an LCD screen.
Along with two pricey, high-end iPhones, Apple is expected to release a lower-cost device with a 6.1-inch LCD display. The LCD iPhone could be equipped with a single-lens camera, compared with the double-lens cameras on the higher-end iPhones.
Estimates suggest this device would be more affordable than its brethren, with a price closer to $550 or $650.
We're also likely to see a revamped Apple Watch.
The leaked image shows a gold Apple Watch with what appears to be an edge-to-edge display and a new watch face with eight complications, or special functions.
The new watch is also expected to come in two new, larger sizes, and have longer battery life, new health-tracking functions, and a faster chip.
Apple will likely announce when iOS 12, Watch OS 5, and tvOS 12 will be released.
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At its WWDC event in June, Apple unveiled the new operating systems for iPhone, iPad, Apple Watch, and Apple TV -- called iOS 12, Watch OS 5, and tvOS 12, respectively.
The new software typically becomes available each fall, which means Apple will almost certainly announce official release dates for each operating system at its event on September 12.
Apple may announce when its AirPower wireless charging pad will be available.
When Apple announced the iPhone 8 and iPhone X a year ago, Apple also gave a "sneak peek" of its own wireless charging pad. Called AirPower, the pad would be able to charge an iPhone, Apple Watch, and its AirPods headphones at the same time, just by placing them on the mat.
Apple said at the time AirPower was "coming in 2018."
We might see an update to AirPods, Apple's very popular wireless earbuds.
Apple introduced AirPods in September 2016, and they've become one of Apple's most warmly- received new products in years. Given that it's been two years since the first generation of AirPods hit store shelves, it may time for Apple to release AirPods 2.
Apple has already announced a new AirPods case that can charge wirelessly, but other new features are still rumored, like water resistance and noise cancellation.
There may be a new iPad that looks a lot more like the iPhone X.
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Apple may be planning to debut a revamped iPad this fall.
According to a Bloomberg report from last November, Apple has been working on a high-end iPad that incorporates some of the features of the iPhone X, like Face ID, no home button, and a nearly edge-to-edge display.
Bloomberg reported at the time that the iPad could be released in 2018.
Apple's most recent iPad release in April was a $330 version targeted at the education market.