diff --git a/Groceries.Data/Items/Item.cs b/Groceries.Data/Items/Item.cs
index ed774da..5ec2e16 100644
--- a/Groceries.Data/Items/Item.cs
+++ b/Groceries.Data/Items/Item.cs
@@ -16,10 +16,6 @@ public class Item
     {
     }
 
-    public Item(string brand, string name) : this(default, brand, name)
-    {
-    }
-
     public Guid Id { get; init; }
     public DateTime UpdatedAt { get; set; }
     public string Brand { get; set; }
diff --git a/Groceries.Data/Transactions/TransactionItem.cs b/Groceries.Data/Transactions/TransactionItem.cs
index 1aa880b..6b2bb25 100644
--- a/Groceries.Data/Transactions/TransactionItem.cs
+++ b/Groceries.Data/Transactions/TransactionItem.cs
@@ -22,7 +22,7 @@ public class TransactionItem
     public decimal Price { get; set; }
     public int Quantity { get; set; }
 
-    public Item? Item { get; init; }
+    public Item? Item { get; set; }
 
     public decimal Amount => Price * Quantity;
 }
diff --git a/Groceries/Transactions/EditTransactionItem.cshtml b/Groceries/Transactions/EditTransactionItem.cshtml
index 796c941..2c0153d 100644
--- a/Groceries/Transactions/EditTransactionItem.cshtml
+++ b/Groceries/Transactions/EditTransactionItem.cshtml
@@ -1,5 +1,5 @@
-@using Groceries.Data;
-@using Microsoft.EntityFrameworkCore;
+@using Groceries.Data
+@using Microsoft.EntityFrameworkCore
 
 @model (Transaction Transaction, TransactionItem TransactionItem)
 @inject AppDbContext dbContext
diff --git a/Groceries/Transactions/NewTransactionItem.cshtml b/Groceries/Transactions/NewTransactionItem.cshtml
index 10c109b..a32457d 100644
--- a/Groceries/Transactions/NewTransactionItem.cshtml
+++ b/Groceries/Transactions/NewTransactionItem.cshtml
@@ -1,23 +1,25 @@
-@using Groceries.Data;
-@using Microsoft.EntityFrameworkCore;
+@using Groceries.Data
+@using Microsoft.EntityFrameworkCore
 
-@model Transaction
+@model (Transaction Transaction, TransactionItem? TransactionItem)
 @inject AppDbContext dbContext
 @{
     ViewBag.Title = "New Transaction Item";
 
     var store = await dbContext.Stores
-        .Where(store => store.Id == Model.StoreId)
+        .Where(store => store.Id == Model.Transaction.StoreId)
         .Select(store => string.Concat(store.Retailer!.Name, " ", store.Name))
         .SingleAsync();
 }
 
 <h1>New Transaction Item</h1>
 
-<div class="form-field">@Model.CreatedAt.ToShortDateString() @Model.CreatedAt.ToShortTimeString() &ndash; @store</div>
+<div class="form-field">
+    @Model.Transaction.CreatedAt.ToShortDateString() @Model.Transaction.CreatedAt.ToShortTimeString() &ndash; @store
+</div>
 
 <form method="post" asp-action="NewTransactionItem">
-    <partial name="_TransactionItemForm" model="null" />
+    <partial name="_TransactionItemForm" model="Model.TransactionItem" />
 
     <div class="row">
         <button class="button button--primary" type="submit">Add</button>
diff --git a/Groceries/Transactions/NewTransactionItem_Modal.cshtml b/Groceries/Transactions/NewTransactionItem_Modal.cshtml
index 79d7c77..424f0e9 100644
--- a/Groceries/Transactions/NewTransactionItem_Modal.cshtml
+++ b/Groceries/Transactions/NewTransactionItem_Modal.cshtml
@@ -1,13 +1,13 @@
 @using Groceries.Data
 
-@model Transaction
+@model (Transaction Transaction, TransactionItem? TransactionItem)
 @{
     Layout = "_Modal";
     ViewBag.Title = "New Transaction Item";
 }
 
 <form class="card__content" id="newTransactionItem" method="post" asp-action="NewTransactionItem" data-action="turbo:submit-end->modal#close">
-    <partial name="_TransactionItemForm" model="null" />
+    <partial name="_TransactionItemForm" model="Model.TransactionItem" />
 </form>
 
 <footer class="card__footer card__footer--shaded row">
diff --git a/Groceries/Transactions/TransactionsController.cs b/Groceries/Transactions/TransactionsController.cs
index f715fbc..77377e9 100644
--- a/Groceries/Transactions/TransactionsController.cs
+++ b/Groceries/Transactions/TransactionsController.cs
@@ -99,20 +99,35 @@ public class TransactionsController : Controller
     }
 
     [HttpGet("new/items/new")]
-    public IActionResult NewTransactionItem()
+    public async Task<IActionResult> NewTransactionItem(long? barcodeData, string? barcodeFormat)
     {
         if (TempData.Peek("NewTransaction") is not string json || JsonSerializer.Deserialize<Transaction>(json) is not Transaction transaction)
         {
             return RedirectToAction(nameof(NewTransaction));
         }
 
+        TransactionItem? transactionItem = null;
+        if (barcodeData != null && barcodeFormat != null)
+        {
+            var item = await dbContext.Items
+                .Where(item => item.Barcodes.Any(barcode => barcode.BarcodeData == barcodeData))
+                .FirstOrDefaultAsync();
+
+            item ??= new Item(id: default);
+            item.Barcodes.Add(new ItemBarcode(item.Id, barcodeData.Value, barcodeFormat));
+
+            // TODO: Fix `MinValue` hack - view models?
+            transactionItem = new TransactionItem(item.Id, decimal.MinValue, int.MinValue) { Item = item };
+        }
+
+        var model = (transaction, transactionItem);
         return Request.IsTurboFrameRequest("modal")
-            ? View($"{nameof(NewTransactionItem)}_Modal", transaction)
-            : View(transaction);
+            ? View($"{nameof(NewTransactionItem)}_Modal", model)
+            : View(model);
     }
 
     [HttpPost("new/items/new")]
-    public async Task<IActionResult> NewTransactionItem(string brand, string name, decimal price, int quantity)
+    public async Task<IActionResult> NewTransactionItem(string brand, string name, decimal price, int quantity, long? barcodeData, string? barcodeFormat)
     {
         if (TempData.Peek("NewTransaction") is not string json || JsonSerializer.Deserialize<Transaction>(json) is not Transaction transaction)
         {
@@ -124,17 +139,18 @@ public class TransactionsController : Controller
             .Select(item => item.Id)
             .SingleOrDefaultAsync();
 
-        if (itemId == default)
+        var item = new Item(itemId, brand, name);
+        if (barcodeData != null && barcodeFormat != null)
         {
-            var item = new Item(brand, name);
-            dbContext.Items.Add(item);
-            await dbContext.SaveChangesAsync();
-            itemId = item.Id;
+            item.Barcodes.Add(new ItemBarcode(itemId, barcodeData.Value, barcodeFormat));
         }
 
+        dbContext.Items.Attach(item);
+        await dbContext.SaveChangesAsync();
+
         // TODO: Handle item already in transaction - merge, replace, error?
 
-        var transactionItem = new TransactionItem(itemId, price, quantity);
+        var transactionItem = new TransactionItem(item.Id, price, quantity) { Item = item };
         transaction.Items.Add(transactionItem);
 
         TempData["NewTransaction"] = JsonSerializer.Serialize(transaction);
@@ -183,18 +199,18 @@ public class TransactionsController : Controller
             .Select(item => item.Id)
             .SingleOrDefaultAsync();
 
-        if (itemId == default)
-        {
-            var item = new Item(brand, name);
-            dbContext.Items.Add(item);
-            await dbContext.SaveChangesAsync();
-            itemId = item.Id;
-        }
+        var item = new Item(itemId, brand, name);
 
-        transactionItem.ItemId = itemId;
+        dbContext.Items.Attach(item);
+        await dbContext.SaveChangesAsync();
+
+        transactionItem.Item = item;
+        transactionItem.ItemId = item.Id;
         transactionItem.Price = price;
         transactionItem.Quantity = quantity;
 
+        // TODO: Handle barcode when editing item - replace, disable?
+
         TempData["NewTransaction"] = JsonSerializer.Serialize(transaction);
 
         return Request.IsTurboFrameRequest("modal")
@@ -243,7 +259,10 @@ public class TransactionsController : Controller
         }
 
         // Work around EF trying to insert items by explicitly tracking them as unchanged
-        dbContext.Items.AttachRange(transaction.Promotions.SelectMany(promotion => promotion.Items));
+        dbContext.Items.AttachRange(
+            transaction.Items
+                .Select(item => item.Item!)
+                .Concat(transaction.Promotions.SelectMany(promotion => promotion.Items)));
 
         dbContext.Transactions.Add(transaction);
         await dbContext.SaveChangesAsync();
diff --git a/Groceries/Transactions/_TransactionItemForm.cshtml b/Groceries/Transactions/_TransactionItemForm.cshtml
index 7e20f10..a878674 100644
--- a/Groceries/Transactions/_TransactionItemForm.cshtml
+++ b/Groceries/Transactions/_TransactionItemForm.cshtml
@@ -25,13 +25,30 @@
         .ToArrayAsync();
 
     var selectedItem = items.SingleOrDefault(item => item.Id == Model?.ItemId);
+
+    var barcode = Model?.Item?.Barcodes.FirstOrDefault();
+
+    var price = Model?.Price >= 0 ? Model.Price : selectedItem?.Price;
+    var quantity = Model?.Quantity >= 1 ? Model.Quantity : (selectedItem?.Quantity ?? 1);
 }
 
 <div data-controller="transaction-item-form">
+    <div class="form-field" data-transaction-item-form-target="barcodeFormField" hidden>
+        <label class="form-field__label" for="transactionItemBarcode">Barcode</label>
+        <div class="form-field__control input">
+            <input type="hidden" name="barcodeFormat" value="@barcode?.Format" data-transaction-item-form-target="barcodeFormat" />
+            <input class="input__control" id="transactionItemBarcode" name="barcodeData" value="@barcode?.BarcodeData" data-transaction-item-form-target="barcodeData" />
+            <button class="input__addon button" formmethod="get" formnovalidate data-action="transaction-item-form#scanBarcode" data-transaction-item-form-target="barcodeButton">
+                @* Barcode scanner icon *@
+                <svg class="icon icon--sm" xmlns="http://www.w3.org/2000/svg" height="24" viewBox="0 -960 960 960" width="24"><path d="M40-120v-200h80v120h120v80H40Zm680 0v-80h120v-120h80v200H720ZM160-240v-480h80v480h-80Zm120 0v-480h40v480h-40Zm120 0v-480h80v480h-80Zm120 0v-480h120v480H520Zm160 0v-480h40v480h-40Zm80 0v-480h40v480h-40ZM40-640v-200h200v80H120v120H40Zm800 0v-120H720v-80h200v200h-80Z" /></svg>
+            </button>
+        </div>
+    </div>
+
     <fieldset class="form-field">
         <legend class="form-field__label">Item</legend>
         <div class="form-field__control input">
-            <input class="input__control flex-2" name="brand" value="@selectedItem?.Brand" placeholder="Brand" list="itemBrands" autocomplete="off" required autofocus data-action="transaction-item-form#filterNames transaction-item-form#setPriceAndQuantity" />
+            <input class="input__control flex-2" name="brand" value="@selectedItem?.Brand" placeholder="Brand" list="itemBrands" autocomplete="off" required autofocus data-action="transaction-item-form#filterNames transaction-item-form#setPriceAndQuantity" data-transaction-item-form-target="brand" />
             <input class="input__control flex-5" name="name" value="@selectedItem?.Name" placeholder="Name" list="itemNames" autocomplete="off" required data-action="transaction-item-form#setPriceAndQuantity" />
 
             <datalist id="itemBrands">
@@ -54,14 +71,14 @@
         <label class="form-field__label" for="transactionItemPrice">Price</label>
         <div class="form-field__control input">
             @*<span class="input__inset">@CultureInfo.CurrentCulture.NumberFormat.CurrencySymbol</span>*@
-            <input class="input__control" id="transactionItemPrice" name="price" value="@Model?.Price" type="number" min="0" step="0.01" required data-transaction-item-form-target="price" />
+            <input class="input__control" id="transactionItemPrice" name="price" value="@price" type="number" min="0" step="0.01" required data-transaction-item-form-target="price" />
         </div>
     </div>
 
     <div class="form-field">
         <label class="form-field__label" for="transactionItemQuantity">Quantity</label>
         <div class="form-field__control input">
-            <input class="input__control" id="transactionItemQuantity" name="quantity" value="@(Model?.Quantity ?? 1)" type="number" min="1" required data-transaction-item-form-target="quantity" />
+            <input class="input__control" id="transactionItemQuantity" name="quantity" value="@quantity" type="number" min="1" required data-transaction-item-form-target="quantity" />
         </div>
     </div>
 </div>
diff --git a/Groceries/wwwroot/js/controllers/modal.js b/Groceries/wwwroot/js/controllers/modal.js
index a3dd297..be2d81a 100644
--- a/Groceries/wwwroot/js/controllers/modal.js
+++ b/Groceries/wwwroot/js/controllers/modal.js
@@ -13,6 +13,10 @@ export default class ModalController extends Controller {
         if (!this.element.open) {
             return;
         }
+        if (event.type === "turbo:submit-end" && (event.detail.formSubmission.method === 0 || !event.detail.success)) {
+            // Don't close modal if form method was GET or submission failed
+            return;
+        }
 
         event.preventDefault();
 
diff --git a/Groceries/wwwroot/js/controllers/transaction-item-form.js b/Groceries/wwwroot/js/controllers/transaction-item-form.js
index b2d890b..2bccd69 100644
--- a/Groceries/wwwroot/js/controllers/transaction-item-form.js
+++ b/Groceries/wwwroot/js/controllers/transaction-item-form.js
@@ -1,7 +1,26 @@
 import { Controller } from "/lib/hotwired/stimulus/dist/stimulus.js";
 
 export default class TransactionItemFormController extends Controller {
-    static targets = ["option", "price", "quantity"];
+    static targets = ["barcodeButton", "barcodeData", "barcodeFormat", "barcodeFormField", "brand", "option", "price", "quantity"];
+
+    #scanning = false;
+    #scanIntervalId;
+    #stream;
+
+    connect() {
+        if ('BarcodeDetector' in globalThis) {
+            this.barcodeFormFieldTarget.hidden = false;
+            if (this.barcodeDataTarget.value) {
+                this.brandTarget.autofocus = false;
+            }
+        }
+    }
+
+    disconnect() {
+        this.barcodeFormFieldTarget.hidden = true;
+        this.brandTarget.autofocus = true;
+        this.stopScanning();
+    }
 
     filterNames(event) {
         for (const option of this.optionTargets) {
@@ -36,4 +55,54 @@ export default class TransactionItemFormController extends Controller {
             }
         }
     }
+
+    async scanBarcode(event) {
+        event?.preventDefault();
+
+        if (this.#scanning) {
+            return;
+        }
+
+        this.#scanning = true;
+        this.barcodeDataTarget.value = "";
+        this.barcodeFormatTarget.value = "";
+
+        this.#stream = await navigator.mediaDevices.getUserMedia({ video: { facingMode: "environment" } });
+
+        const video = document.createElement("video");
+        video.srcObject = this.#stream;
+        await video.play();
+
+        const detector = new BarcodeDetector();
+
+        this.#scanIntervalId = setInterval(async () => {
+            const barcodes = await detector.detect(video);
+            if (barcodes.length === 0) {
+                return;
+            }
+
+            const barcode = barcodes[0];
+            this.barcodeDataTarget.value = barcode.rawValue;
+            this.barcodeFormatTarget.value = barcode.format;
+
+            this.stopScanning();
+
+            const form = this.element.closest("form");
+            for (const element of form.elements) {
+                element.disabled = !element.name.startsWith("barcode");
+            }
+
+            form.requestSubmit(this.barcodeButtonTarget);
+        }, 250);
+    }
+
+    stopScanning() {
+        if (this.#scanning) {
+            this.#stream?.getTracks()
+                .forEach(track => track.stop());
+
+            clearInterval(this.#scanIntervalId);
+            this.#scanning = false;
+        }
+    }
 }