Most "missing" items are listed for sale, sitting in a trade, recycled, attached to a Pal, or were never tradable copies in the first place. Work through the checks below, then look at your Transaction History on the website to see exactly what happened.
Where could my item be?
Hidden: if you or someone using your device tapped Hide on an item, it leaves your Closet and your collections but you still own it. Open My Items, go to Collections, and check your Hidden collection. See How do I organize my items with Collections, Favorites, and Hidden?
Listed on the Marketplace: a listed item leaves your inventory until it sells or you remove the listing. Expired listings stay under your listings for a while so you can relist them. If you leave them there, the items come back to you on a later login.
In a trade: items you add to a trade leave your inventory right away. If the trade was canceled or never finished, open the chat with that player and collect or cancel it.
Recycled: recycling removes items for good and gives you Threads or Bubbles instead.
Attached to a Pal: accessories you put on a Pal are bound to that Pal and show up with it, not in your clothing.
Unopened: items from a chest, Blind Box, or gift stay packed until you open them.
Expired: unused Blind Boxes expire when their Blind Box ends and are removed from your inventory.
Wrong account: check you're logged in to the account that owned the item.
How do I see who I traded an item to?
Log in at https://highrise.game/account/transaction-history. Transaction History lists the last 40 days of your trades, Marketplace sales and purchases, Blind Box pulls, recycling, and more, newest first. Find the date the item disappeared and the entry tells you what happened to it.
The item shows "0 Owned" in a trade, but I can wear it
You own an Account Bound copy. Account Bound copies can be worn but never traded or sold. See What does Account Bound mean?
Can Highrise give back an item I traded, sold, or recycled?
Completed trades and Marketplace sales are final. Recycling can sometimes be reversed if you ask soon enough; see Can I undo an accidental Recycle? If you think someone took items from your account, that's an account security case, not an inventory one: see My account was hacked.
Still can't find it?
Contact Support with your username, the item name, roughly when you last saw it, and what you did with it before it went missing (listed, traded, recycled, put on a Pal). A screenshot helps. Never share your password or Safety Lock PIN.