diff --git a/src/main/java/de/epiceric/shopchest/nms/ShulkerBoxMeta.java b/src/main/java/de/epiceric/shopchest/nms/ShulkerBoxMeta.java
new file mode 100644
index 0000000..cb6b18e
--- /dev/null
+++ b/src/main/java/de/epiceric/shopchest/nms/ShulkerBoxMeta.java
@@ -0,0 +1,106 @@
+package de.epiceric.shopchest.nms;
+
+import de.epiceric.shopchest.ShopChest;
+import de.epiceric.shopchest.utils.Utils;
+import org.bukkit.inventory.ItemStack;
+
+import java.lang.reflect.InvocationTargetException;
+import java.util.HashMap;
+import java.util.Map;
+
+public class ShulkerBoxMeta {
+
+    public static Map<Integer, ItemStack> getContents(ItemStack shulkerBox) {
+        try {
+            Class<?> craftItemStackClass = Utils.getCraftClass("inventory.CraftItemStack");
+
+            if (craftItemStackClass == null) {
+                ShopChest.getInstance().debug("Failed to get NBTContents: Could not find CraftItemStack class");
+                return null;
+            }
+
+            Object nmsStack = craftItemStackClass.getMethod("asNMSCopy", ItemStack.class).invoke(null, shulkerBox);
+            if (nmsStack == null) {
+                ShopChest.getInstance().debug("Failed to get NBTContents: asNMSCopy returned null");
+                return null;
+            }
+
+            Object hasTag = nmsStack.getClass().getMethod("hasTag").invoke(nmsStack);
+            if (hasTag == null || !(hasTag instanceof Boolean)) {
+                ShopChest.getInstance().debug("Failed to get NBTContents: hasTag returned null");
+                return null;
+            }
+
+            if (!(boolean) hasTag) {
+                ShopChest.getInstance().debug("Failed to get NBTContents: ItemStack has no tag");
+                return null;
+            }
+
+            Object nbtTagCompound = nmsStack.getClass().getMethod("getTag").invoke(nmsStack);
+            if (nbtTagCompound == null) {
+                ShopChest.getInstance().debug("Failed to get NBTContents: getTag returned null");
+                return null;
+            }
+
+            Object blockEntityTagObject = nbtTagCompound.getClass().getMethod("getCompound", String.class).invoke(nbtTagCompound, "BlockEntityTag");
+            if (blockEntityTagObject == null) {
+                ShopChest.getInstance().debug("Failed to get NBTContents: getCompound returned null");
+                return null;
+            }
+
+            Object itemsObject = blockEntityTagObject.getClass().getMethod("getList", String.class, int.class).invoke(blockEntityTagObject, "Items", 10);
+            if (itemsObject == null) {
+                ShopChest.getInstance().debug("Failed to get NBTContents: getList returned null");
+                return null;
+            }
+
+            Object sizeObject = itemsObject.getClass().getMethod("size").invoke(itemsObject);
+            if (sizeObject == null) {
+                ShopChest.getInstance().debug("Failed to get NBTContents: size returned null or not an integer");
+                return null;
+            }
+
+            int size = (Integer) sizeObject;
+
+            Map<Integer, ItemStack> contentSlots = new HashMap<>();
+
+            for (int i = 0; i < size; i++) {
+                Object itemTag = itemsObject.getClass().getMethod("get", int.class).invoke(itemsObject, i);
+                if (itemTag == null) {
+                    ShopChest.getInstance().debug("Failed to get NBTContents: get returned null");
+                    continue;
+                }
+
+                Object nmsStack2 = nmsStack.getClass().getConstructor(nbtTagCompound.getClass()).newInstance(itemTag);
+                if (nmsStack2 == null) {
+                    ShopChest.getInstance().debug("Failed to get NBTContents: Could not instantiate ItemStack with compound");
+                    continue;
+                }
+
+                Object slotObject = itemTag.getClass().getMethod("getInt", String.class).invoke(itemTag, "Slot");
+                if (slotObject == null || !(slotObject instanceof Integer)) {
+                    ShopChest.getInstance().debug("Failed to get NBTContents: getInt returned null or not an integer");
+                    continue;
+                }
+
+                Object itemStack = craftItemStackClass.getMethod("asBukkitCopy", nmsStack2.getClass()).invoke(null, nmsStack2);
+                if (itemStack == null || !(itemStack instanceof ItemStack)) {
+                    ShopChest.getInstance().debug("Failed to get NBTContents: asBukkitCopy returned null or not an ItemStack");
+                    continue;
+                }
+
+                contentSlots.put((Integer) slotObject, (ItemStack) itemStack);
+            }
+
+            return contentSlots;
+
+        } catch (NoSuchMethodException | IllegalAccessException | InvocationTargetException | InstantiationException  e) {
+            ShopChest.getInstance().getLogger().severe("Failed to get NBTContents with reflection");
+            ShopChest.getInstance().debug("Failed to get NBTContents with reflection");
+            ShopChest.getInstance().debug(e);
+        }
+
+        return null;
+    }
+
+}
diff --git a/src/main/java/de/epiceric/shopchest/utils/Utils.java b/src/main/java/de/epiceric/shopchest/utils/Utils.java
index d351e0f..ccbfaf6 100644
--- a/src/main/java/de/epiceric/shopchest/utils/Utils.java
+++ b/src/main/java/de/epiceric/shopchest/utils/Utils.java
@@ -1,7 +1,9 @@
 package de.epiceric.shopchest.utils;
 
+import com.google.common.collect.ImmutableList;
 import de.epiceric.shopchest.ShopChest;
 import de.epiceric.shopchest.nms.CustomBookMeta;
+import de.epiceric.shopchest.nms.ShulkerBoxMeta;
 import org.bukkit.Bukkit;
 import org.bukkit.Material;
 import org.bukkit.configuration.InvalidConfigurationException;
@@ -19,9 +21,29 @@ import java.lang.reflect.InvocationTargetException;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.HashMap;
+import java.util.Map;
 
 public class Utils {
 
+    private static final ImmutableList<Material> SHULKER_BOX_MATERIALS = new ImmutableList.Builder<Material>()
+            .add(Material.BLACK_SHULKER_BOX)
+            .add(Material.BLUE_SHULKER_BOX)
+            .add(Material.BROWN_SHULKER_BOX)
+            .add(Material.CYAN_SHULKER_BOX)
+            .add(Material.GRAY_SHULKER_BOX)
+            .add(Material.GREEN_SHULKER_BOX)
+            .add(Material.LIGHT_BLUE_SHULKER_BOX)
+            .add(Material.LIME_SHULKER_BOX)
+            .add(Material.MAGENTA_SHULKER_BOX)
+            .add(Material.ORANGE_SHULKER_BOX)
+            .add(Material.PINK_SHULKER_BOX)
+            .add(Material.PURPLE_SHULKER_BOX)
+            .add(Material.RED_SHULKER_BOX)
+            .add(Material.SILVER_SHULKER_BOX)
+            .add(Material.WHITE_SHULKER_BOX)
+            .add(Material.YELLOW_SHULKER_BOX)
+            .build();
+
     /**
      * Check if two items are similar to each other
      * @param itemStack1 The first item
@@ -82,6 +104,13 @@ public class Utils {
 
             if (bsMeta1.hasBlockState()) similar &= (bsMeta1.getBlockState().equals(bsMeta2.getBlockState()));
 
+            if (getMajorVersion() >= 11 && SHULKER_BOX_MATERIALS.contains(itemStack1.getType())) {
+                Map<Integer, ItemStack> contents1 = ShulkerBoxMeta.getContents(itemStack1);
+                Map<Integer, ItemStack> contents2 = ShulkerBoxMeta.getContents(itemStack2);
+
+                if (contents1 != null) similar &= contents1.equals(contents2);
+            }
+
         } else if (itemMeta1 instanceof BookMeta) {
             BookMeta bookMeta1 = (BookMeta) itemMeta1;
             BookMeta bookMeta2 = (BookMeta) itemMeta2;