diff --git a/components/shop/shop-content.tsx b/components/shop/shop-content.tsx
index 2915702..b910322 100644
--- a/components/shop/shop-content.tsx
+++ b/components/shop/shop-content.tsx
@@ -8,8 +8,10 @@ import { Button } from "@/components/ui/button";
 import { Card, CardContent } from "@/components/ui/card";
 import { useToast } from "@/components/ui/toast-provider";
 import { HABIT_PET_DATA_UPDATED_EVENT } from "@/lib/app-events";
+import { getAvatarCustomization } from "@/lib/avatar-customization-storage";
+import type { AvatarCustomization } from "@/lib/avatar-customization-storage";
 import { DEFAULT_GRAY_COLOR } from "@/lib/character/presets";
-import { getRoomBackground } from "@/lib/room-backgrounds";
+import { getRoomBackground, normalizeRoomBackgroundId } from "@/lib/room-backgrounds";
 import {
   equipShopItem,
   getShopInventory,
@@ -23,6 +25,8 @@ import {
 } from "@/lib/shop-catalog";
 import { cn } from "@/lib/utils";
 
+import { ShopItemPreviewModal } from "@/components/shop/shop-item-preview-modal";
+
 const SHOP_LAYER_ORDER: ShopLayerId[] = [
   "head",
   "torso",
@@ -39,6 +43,7 @@ function ShopItemCard({
   isPending,
   onPurchase,
   onEquipToggle,
+  onPreview,
 }: {
   item: ShopItemRecord;
   owned: boolean;
@@ -47,6 +52,7 @@ function ShopItemCard({
   isPending: boolean;
   onPurchase: () => void;
   onEquipToggle: () => void;
+  onPreview: () => void;
 }) {
   const room = item.type === "room" ? getRoomBackground(item.id) : null;
 
@@ -101,16 +107,29 @@ function ShopItemCard({
           </div>
         </div>
 
-        <Button
-          className="mt-auto h-auto min-h-9 w-full whitespace-normal px-2 py-2 text-center text-[10px] leading-snug"
-          variant={owned && equipped ? "default" : "outline"}
-          disabled={
-            isPending || (!owned && !canAfford) || (owned && item.type === "room" && equipped)
-          }
-          onClick={owned ? onEquipToggle : onPurchase}
-        >
-          {actionLabel}
-        </Button>
+        <div className="mt-auto grid grid-cols-2 gap-2">
+          <Button
+            type="button"
+            className="h-auto min-h-9 whitespace-normal px-2 py-2 text-[10px] leading-snug"
+            variant="outline"
+            disabled={isPending}
+            onClick={onPreview}
+          >
+            Preview
+          </Button>
+          <Button
+            className="h-auto min-h-9 whitespace-normal px-2 py-2 text-[10px] leading-snug"
+            variant={owned && equipped ? "default" : "outline"}
+            disabled={
+              isPending ||
+              (!owned && !canAfford) ||
+              (owned && item.type === "room" && equipped)
+            }
+            onClick={owned ? onEquipToggle : onPurchase}
+          >
+            {actionLabel}
+          </Button>
+        </div>
       </CardContent>
     </Card>
   );
@@ -125,16 +144,27 @@ export function ShopContent() {
   const [coins, setCoins] = useState<number | null>(null);
   const [error, setError] = useState<string | null>(null);
   const [pendingItemId, setPendingItemId] = useState<string | null>(null);
+  const [baseCustomization, setBaseCustomization] =
+    useState<AvatarCustomization | null>(null);
+  const [previewItem, setPreviewItem] = useState<ShopItemRecord | null>(null);
 
   const refreshShop = useCallback(async () => {
     try {
       setError(null);
-      const inventory = await getShopInventory();
+      const [inventory, customization] = await Promise.all([
+        getShopInventory(),
+        getAvatarCustomization(),
+      ]);
       setItems(inventory.items);
       setOwnedItemIds(inventory.ownedItemIds);
       setEquippedItems(inventory.equippedItems);
       setEquippedRoomBackground(inventory.equippedRoomBackground);
       setCoins(inventory.coins);
+      setBaseCustomization({
+        ...customization,
+        equippedItems: inventory.equippedItems,
+        roomBackground: normalizeRoomBackgroundId(inventory.equippedRoomBackground),
+      });
     } catch (refreshError) {
       setError(
         refreshError instanceof Error
@@ -214,6 +244,12 @@ export function ShopContent() {
 
   return (
     <>
+      <ShopItemPreviewModal
+        item={previewItem}
+        baseCustomization={baseCustomization}
+        onClose={() => setPreviewItem(null)}
+      />
+
       <div className="mb-5 flex items-center justify-between gap-3 border-2 border-border bg-muted/40 px-4 py-3 shadow-[var(--retro-shadow-sm)]">
         <span className="text-[10px] uppercase tracking-wider text-muted-foreground">
           Your balance
@@ -253,6 +289,7 @@ export function ShopContent() {
                   isPending={pendingItemId === item.id}
                   onPurchase={() => void handlePurchase(item.id)}
                   onEquipToggle={() => void handleEquipToggle(item)}
+                  onPreview={() => setPreviewItem(item)}
                 />
               ))}
             </div>
@@ -275,6 +312,7 @@ export function ShopContent() {
                   isPending={pendingItemId === item.id}
                   onPurchase={() => void handlePurchase(item.id)}
                   onEquipToggle={() => void handleEquipToggle(item)}
+                  onPreview={() => setPreviewItem(item)}
                 />
               ))}
             </div>
diff --git a/components/shop/shop-item-preview-modal.tsx b/components/shop/shop-item-preview-modal.tsx
new file mode 100644
index 0000000..8fb704b
--- /dev/null
+++ b/components/shop/shop-item-preview-modal.tsx
@@ -0,0 +1,113 @@
+"use client";
+
+import { X } from "lucide-react";
+import { useEffect } from "react";
+
+import { CharacterLayerPreview } from "@/components/character/character-layer-preview";
+import { ParallaxRoomBackground } from "@/components/pet/parallax-room-background";
+import { Button } from "@/components/ui/button";
+import type { AvatarCustomization } from "@/lib/avatar-customization-storage";
+import { buildShopItemPreviewCustomization } from "@/lib/shop-preview";
+import type { ShopItemRecord } from "@/lib/shop-catalog";
+import {
+  normalizeRoomBackgroundId,
+  type RoomBackgroundId,
+} from "@/lib/room-backgrounds";
+
+type ShopItemPreviewModalProps = {
+  item: ShopItemRecord | null;
+  baseCustomization: AvatarCustomization | null;
+  onClose: () => void;
+};
+
+export function ShopItemPreviewModal({
+  item,
+  baseCustomization,
+  onClose,
+}: ShopItemPreviewModalProps) {
+  useEffect(() => {
+    if (!item) {
+      return;
+    }
+
+    const handleKeyDown = (event: KeyboardEvent) => {
+      if (event.key === "Escape") {
+        onClose();
+      }
+    };
+
+    window.addEventListener("keydown", handleKeyDown);
+    return () => {
+      window.removeEventListener("keydown", handleKeyDown);
+    };
+  }, [item, onClose]);
+
+  if (!item || !baseCustomization) {
+    return null;
+  }
+
+  const previewCustomization = buildShopItemPreviewCustomization(
+    baseCustomization,
+    item,
+  );
+  const roomId = normalizeRoomBackgroundId(
+    previewCustomization.roomBackground,
+  ) as RoomBackgroundId;
+
+  return (
+    <div
+      className="fixed inset-0 z-[70] flex items-end justify-center bg-black/70 p-4 sm:items-center"
+      role="dialog"
+      aria-modal="true"
+      aria-labelledby="shop-preview-title"
+      onClick={onClose}
+    >
+      <div
+        className="w-full max-w-lg border-2 border-border bg-card shadow-[var(--retro-shadow)]"
+        onClick={(event) => event.stopPropagation()}
+      >
+        <div className="flex items-start justify-between gap-3 border-b-2 border-border px-4 py-3">
+          <div className="min-w-0">
+            <p
+              id="shop-preview-title"
+              className="text-[10px] uppercase tracking-wider text-muted-foreground"
+            >
+              Preview on your pet
+            </p>
+            <p className="mt-1 truncate text-sm">{item.name}</p>
+          </div>
+          <Button
+            type="button"
+            size="icon"
+            variant="ghost"
+            className="h-8 w-8 shrink-0"
+            aria-label="Close preview"
+            onClick={onClose}
+          >
+            <X className="h-4 w-4" />
+          </Button>
+        </div>
+
+        <div className="p-4">
+          <div className="tamagotchi-lcd relative aspect-[4/3] w-full overflow-hidden">
+            <ParallaxRoomBackground roomId={roomId} interactive={false} />
+            <div className="relative z-10 flex h-full items-center justify-center">
+              <CharacterLayerPreview
+                colors={previewCustomization.colors}
+                variants={previewCustomization.variants}
+                equippedItems={previewCustomization.equippedItems}
+                scale={8}
+                compact
+                className="!h-auto max-h-none"
+              />
+            </div>
+            <div className="pointer-events-none absolute inset-x-0 bottom-0 z-[2] h-8 bg-gradient-to-t from-black/35 to-transparent" />
+          </div>
+          <p className="mt-3 text-center text-[10px] text-muted-foreground">
+            This preview does not equip or purchase the item.
+          </p>
+        </div>
+      </div>
+    </div>
+  );
+}
diff --git a/lib/shop-preview.ts b/lib/shop-preview.ts
new file mode 100644
index 0000000..17640a7
--- /dev/null
+++ b/lib/shop-preview.ts
@@ -0,0 +1,34 @@
+import type { AvatarCustomization } from "@/lib/avatar-customization-storage";
+import { parseVariantId, parseShopStyleItem, type ShopItemRecord } from "@/lib/shop-catalog";
+import { normalizeRoomBackgroundId } from "@/lib/room-backgrounds";
+
+/** Build a non-persisted avatar state showing how a shop item would look. */
+export function buildShopItemPreviewCustomization(
+  base: AvatarCustomization,
+  item: ShopItemRecord,
+): AvatarCustomization {
+  if (item.type === "room") {
+    return {
+      ...base,
+      roomBackground: normalizeRoomBackgroundId(item.id),
+    };
+  }
+
+  const style = parseShopStyleItem(item.id, item.type);
+  if (!style) {
+    return base;
+  }
+
+  const nextEquipped = [
+    ...base.equippedItems.filter((equippedId) => {
+      const equippedStyle = parseVariantId(equippedId);
+      return equippedStyle?.layerId !== style.layerId;
+    }),
+    item.id,
+  ];
+
+  return {
+    ...base,
+    equippedItems: nextEquipped,
+  };
+}