diff --git a/app/Models/Commons/Tag.php b/app/Models/Commons/Tag.php
new file mode 100644
index 0000000..9e47c95
--- /dev/null
+++ b/app/Models/Commons/Tag.php
@@ -0,0 +1,56 @@
+<?php
+
+namespace App\Models\Commons;
+
+use App\Models\Materials\Material;
+use App\Models\Products\Bom;
+use App\Models\Products\Part;
+use App\Models\Products\Product;
+use App\Models\Tenants\Tenant;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\Relations\MorphToMany;
+
+class Tag extends Model
+{
+    protected $fillable = ['tenant_id', 'name'];
+
+    // 테넌트 관계(옵션)
+    public function tenant(): BelongsTo
+    {
+        return $this->belongsTo(Tenant::class);
+    }
+
+
+    /**
+     * 제품(Product)와 연결 (N:M, 폴리모픽)
+     */
+    public function products(): MorphToMany
+    {
+        return $this->morphedByMany(Product::class, 'taggable');
+    }
+
+    /**
+     * 부품(Part)와 연결 (N:M, 폴리모픽)
+     */
+    public function parts(): MorphToMany
+    {
+        return $this->morphedByMany(Part::class, 'taggable');
+    }
+
+    /**
+     * 자재(Material)와 연결 (N:M, 폴리모픽)
+     */
+    public function materials(): MorphToMany
+    {
+        return $this->morphedByMany(Material::class, 'taggable');
+    }
+
+    /**
+     * BOM(Bill of Materials)와 연결 (N:M, 폴리모픽)
+     */
+    public function boms(): MorphToMany
+    {
+        return $this->morphedByMany(Bom::class, 'taggable');
+    }
+}
diff --git a/app/Models/MainRequest.php b/app/Models/MainRequest.php
index bb83d92..726a55a 100644
--- a/app/Models/MainRequest.php
+++ b/app/Models/MainRequest.php
@@ -3,6 +3,7 @@
 namespace App\Models;
 
 use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\HasMany;
 use Illuminate\Database\Eloquent\SoftDeletes;
 
 class MainRequest extends Model
@@ -28,7 +29,7 @@ class MainRequest extends Model
     /**
      * 전체 이력(흐름) 리스트
      */
-    public function flows()
+    public function flows(): HasMany
     {
         return $this->hasMany(MainRequestFlow::class, 'main_request_id');
     }
diff --git a/app/Models/MainRequestFlow.php b/app/Models/MainRequestFlow.php
index 23acb43..c321d3c 100644
--- a/app/Models/MainRequestFlow.php
+++ b/app/Models/MainRequestFlow.php
@@ -2,7 +2,9 @@
 
 namespace App\Models;
 
-use Illuminate\Database\Eloquent\Model;
+use App\Models\MainRequest;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\Relations\MorphTo;
 
 class MainRequestFlow extends Model
 {
@@ -26,7 +28,7 @@ class MainRequestFlow extends Model
     /**
      * 메인 업무 엔터티
      */
-    public function mainRequest()
+    public function mainRequest(): BelongsTo
     {
         return $this->belongsTo(MainRequest::class, 'main_request_id');
     }
@@ -34,7 +36,7 @@ public function mainRequest()
     /**
      * 폴리모픽 관계(견적, 주문, 발주 등)
      */
-    public function flowable()
+    public function flowable(): MorphTo
     {
         return $this->morphTo();
     }
diff --git a/app/Models/Materials/Material.php b/app/Models/Materials/Material.php
index 2dbcf38..7526d2f 100644
--- a/app/Models/Materials/Material.php
+++ b/app/Models/Materials/Material.php
@@ -2,7 +2,8 @@
 
 namespace App\Models\Materials;
 
-use App\Models\File;
+use App\Models\Commons\File;
+use App\Models\Commons\Tag;
 use App\Models\Qualitys\Lot;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\SoftDeletes;
@@ -35,8 +36,15 @@ public function lots()
         return $this->hasMany(Lot::class, 'material_id');
     }
 
+    // 파일 목록 (N:M, 폴리모픽)
     public function files()
     {
         return $this->morphMany(File::class, 'fileable');
     }
+
+    // 태그 목록 (N:M, 폴리모픽)
+    public function tags()
+    {
+        return $this->morphToMany(Tag::class, 'taggable');
+    }
 }
diff --git a/app/Models/Products/Bom.php b/app/Models/Products/Bom.php
index 472145f..de61b4b 100644
--- a/app/Models/Products/Bom.php
+++ b/app/Models/Products/Bom.php
@@ -3,6 +3,7 @@
 namespace App\Models\Products;
 
 use App\Models\Commons\File;
+use App\Models\Commons\Tag;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\SoftDeletes;
 
@@ -23,4 +24,16 @@ public function items() {
     public function image() {
         return $this->belongsTo(File::class, 'image_file_id');
     }
+
+    // 파일 목록 (N:M, 폴리모픽)
+    public function files()
+    {
+        return $this->morphMany(File::class, 'fileable');
+    }
+
+    // 태그 목록 (N:M, 폴리모픽)
+    public function tags()
+    {
+        return $this->morphToMany(Tag::class, 'taggable');
+    }
 }
diff --git a/app/Models/Products/Part.php b/app/Models/Products/Part.php
index 7a9d7b1..447c72b 100644
--- a/app/Models/Products/Part.php
+++ b/app/Models/Products/Part.php
@@ -1,9 +1,8 @@
 <?php
 
-namespace App\Models;
-
 namespace App\Models\Products;
 
+use App\Models\Commons\Tag;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\SoftDeletes;
 
@@ -18,4 +17,10 @@ public function category() {
     public function partType() {
         return $this->belongsTo(CommonCode::class, 'part_type_id');
     }
+
+    // 태그 목록 (N:M, 폴리모픽)
+    public function tags()
+    {
+        return $this->morphToMany(Tag::class, 'taggable');
+    }
 }
diff --git a/app/Models/Products/Product.php b/app/Models/Products/Product.php
index dec6da5..d0b9f1e 100644
--- a/app/Models/Products/Product.php
+++ b/app/Models/Products/Product.php
@@ -2,6 +2,8 @@
 
 namespace App\Models\Products;
 
+use App\Models\Commons\File;
+use App\Models\Commons\Tag;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\SoftDeletes;
 
@@ -17,8 +19,15 @@ public function boms() {
         return $this->hasMany(Bom::class);
     }
 
+    // 파일 목록 (N:M, 폴리모픽)
     public function files()
     {
         return $this->morphMany(File::class, 'fileable');
     }
+
+    // 태그 목록 (N:M, 폴리모픽)
+    public function tags()
+    {
+        return $this->morphToMany(Tag::class, 'taggable');
+    }
 }