diff --git a/LOGICAL_RELATIONSHIPS.md b/LOGICAL_RELATIONSHIPS.md
index 2058dec..a0680e2 100644
--- a/LOGICAL_RELATIONSHIPS.md
+++ b/LOGICAL_RELATIONSHIPS.md
@@ -1,6 +1,6 @@
 # 논리적 데이터베이스 관계 문서
 
-> **자동 생성**: 2025-12-19 16:48:57
+> **자동 생성**: 2025-12-20 12:21:53
 > **소스**: Eloquent 모델 관계 분석
 
 ## 📊 모델별 관계 현황
diff --git a/app/Models/SystemFieldDefinition.php b/app/Models/SystemFieldDefinition.php
new file mode 100644
index 0000000..a5e03b9
--- /dev/null
+++ b/app/Models/SystemFieldDefinition.php
@@ -0,0 +1,101 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Collection;
+
+/**
+ * 시스템 필드 정의 모델
+ *
+ * 각 소스 테이블(items, tenants, users)의 시스템 필드를 정의합니다.
+ * 테넌트별 item_fields 시딩 시 참조하는 마스터 데이터입니다.
+ */
+class SystemFieldDefinition extends Model
+{
+    protected $fillable = [
+        'source_table',
+        'source_table_label',
+        'field_key',
+        'field_name',
+        'field_type',
+        'order_no',
+        'is_required',
+        'is_seed_default',
+        'default_value',
+        'options',
+        'is_active',
+    ];
+
+    protected $casts = [
+        'order_no' => 'integer',
+        'is_required' => 'boolean',
+        'is_seed_default' => 'boolean',
+        'is_active' => 'boolean',
+        'options' => 'array',
+    ];
+
+    /**
+     * 소스 테이블 목록 조회
+     */
+    public static function getSourceTables(): Collection
+    {
+        return self::query()
+            ->select('source_table', 'source_table_label')
+            ->where('is_active', true)
+            ->groupBy('source_table', 'source_table_label')
+            ->orderBy('source_table')
+            ->get();
+    }
+
+    /**
+     * 특정 소스 테이블의 필드 목록 조회
+     */
+    public static function getFieldsFor(string $sourceTable, bool $onlyActive = true): Collection
+    {
+        $query = self::query()
+            ->where('source_table', $sourceTable)
+            ->orderBy('order_no');
+
+        if ($onlyActive) {
+            $query->where('is_active', true);
+        }
+
+        return $query->get();
+    }
+
+    /**
+     * 특정 소스 테이블의 기본 시딩 대상 필드 목록 조회
+     */
+    public static function getSeedDefaultFieldsFor(string $sourceTable): Collection
+    {
+        return self::query()
+            ->where('source_table', $sourceTable)
+            ->where('is_active', true)
+            ->where('is_seed_default', true)
+            ->orderBy('order_no')
+            ->get();
+    }
+
+    /**
+     * 특정 소스 테이블의 필드 수 조회
+     */
+    public static function getFieldCountFor(string $sourceTable): int
+    {
+        return self::query()
+            ->where('source_table', $sourceTable)
+            ->where('is_active', true)
+            ->count();
+    }
+
+    /**
+     * 모든 소스 테이블의 시스템 필드 키 목록
+     */
+    public static function getAllSystemFieldKeys(string $sourceTable): array
+    {
+        return self::query()
+            ->where('source_table', $sourceTable)
+            ->pluck('field_key')
+            ->toArray();
+    }
+}
diff --git a/database/migrations/2025_12_20_122054_add_source_table_index_to_system_field_definitions_table.php b/database/migrations/2025_12_20_122054_add_source_table_index_to_system_field_definitions_table.php
new file mode 100644
index 0000000..c3df892
--- /dev/null
+++ b/database/migrations/2025_12_20_122054_add_source_table_index_to_system_field_definitions_table.php
@@ -0,0 +1,29 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /**
+     * Run the migrations.
+     * source_table 단독 인덱스 추가 - 쿼리 성능 향상
+     */
+    public function up(): void
+    {
+        Schema::table('system_field_definitions', function (Blueprint $table) {
+            $table->index('source_table', 'idx_source_table');
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::table('system_field_definitions', function (Blueprint $table) {
+            $table->dropIndex('idx_source_table');
+        });
+    }
+};
diff --git a/database/seeders/SystemFieldDefinitionSeeder.php b/database/seeders/SystemFieldDefinitionSeeder.php
new file mode 100644
index 0000000..672f08f
--- /dev/null
+++ b/database/seeders/SystemFieldDefinitionSeeder.php
@@ -0,0 +1,85 @@
+<?php
+
+namespace Database\Seeders;
+
+use App\Models\SystemFieldDefinition;
+use Illuminate\Database\Seeder;
+
+class SystemFieldDefinitionSeeder extends Seeder
+{
+    /**
+     * Run the database seeds.
+     */
+    public function run(): void
+    {
+        $definitions = [
+            // ========================================
+            // items 테이블 시스템 필드
+            // ========================================
+            ...array_map(fn($field) => array_merge($field, [
+                'source_table' => 'items',
+                'source_table_label' => '품목',
+            ]), [
+                ['field_key' => 'code', 'field_name' => '품목코드', 'field_type' => 'textbox', 'is_required' => true, 'is_seed_default' => true, 'order_no' => 1],
+                ['field_key' => 'name', 'field_name' => '품목명', 'field_type' => 'textbox', 'is_required' => true, 'is_seed_default' => true, 'order_no' => 2],
+                ['field_key' => 'item_type', 'field_name' => '품목유형', 'field_type' => 'dropdown', 'is_required' => true, 'is_seed_default' => true, 'order_no' => 3, 'options' => json_encode([
+                    ['label' => '제품', 'value' => 'product'],
+                    ['label' => '자재', 'value' => 'material'],
+                    ['label' => '반제품', 'value' => 'semi'],
+                ])],
+                ['field_key' => 'unit', 'field_name' => '단위', 'field_type' => 'dropdown', 'is_required' => true, 'is_seed_default' => true, 'order_no' => 4],
+                ['field_key' => 'category_id', 'field_name' => '카테고리', 'field_type' => 'dropdown', 'is_required' => false, 'is_seed_default' => true, 'order_no' => 5],
+                ['field_key' => 'description', 'field_name' => '설명', 'field_type' => 'textarea', 'is_required' => false, 'is_seed_default' => false, 'order_no' => 6],
+                ['field_key' => 'is_active', 'field_name' => '활성화', 'field_type' => 'checkbox', 'is_required' => false, 'is_seed_default' => true, 'order_no' => 7, 'default_value' => 'true'],
+            ]),
+
+            // ========================================
+            // tenants 테이블 시스템 필드
+            // ========================================
+            ...array_map(fn($field) => array_merge($field, [
+                'source_table' => 'tenants',
+                'source_table_label' => '테넌트',
+            ]), [
+                ['field_key' => 'company_name', 'field_name' => '회사명', 'field_type' => 'textbox', 'is_required' => true, 'is_seed_default' => true, 'order_no' => 1],
+                ['field_key' => 'code', 'field_name' => '회사코드', 'field_type' => 'textbox', 'is_required' => true, 'is_seed_default' => true, 'order_no' => 2],
+                ['field_key' => 'email', 'field_name' => '이메일', 'field_type' => 'textbox', 'is_required' => false, 'is_seed_default' => true, 'order_no' => 3],
+                ['field_key' => 'phone', 'field_name' => '전화번호', 'field_type' => 'textbox', 'is_required' => false, 'is_seed_default' => true, 'order_no' => 4],
+                ['field_key' => 'address', 'field_name' => '주소', 'field_type' => 'textarea', 'is_required' => false, 'is_seed_default' => false, 'order_no' => 5],
+                ['field_key' => 'business_num', 'field_name' => '사업자번호', 'field_type' => 'textbox', 'is_required' => false, 'is_seed_default' => true, 'order_no' => 6],
+                ['field_key' => 'corp_reg_no', 'field_name' => '법인등록번호', 'field_type' => 'textbox', 'is_required' => false, 'is_seed_default' => false, 'order_no' => 7],
+                ['field_key' => 'ceo_name', 'field_name' => '대표자명', 'field_type' => 'textbox', 'is_required' => false, 'is_seed_default' => true, 'order_no' => 8],
+                ['field_key' => 'homepage', 'field_name' => '홈페이지', 'field_type' => 'textbox', 'is_required' => false, 'is_seed_default' => false, 'order_no' => 9],
+                ['field_key' => 'fax', 'field_name' => '팩스', 'field_type' => 'textbox', 'is_required' => false, 'is_seed_default' => false, 'order_no' => 10],
+                ['field_key' => 'tenant_type', 'field_name' => '테넌트유형', 'field_type' => 'dropdown', 'is_required' => false, 'is_seed_default' => false, 'order_no' => 11],
+                ['field_key' => 'max_users', 'field_name' => '최대사용자수', 'field_type' => 'number', 'is_required' => false, 'is_seed_default' => false, 'order_no' => 12],
+            ]),
+
+            // ========================================
+            // users 테이블 시스템 필드
+            // ========================================
+            ...array_map(fn($field) => array_merge($field, [
+                'source_table' => 'users',
+                'source_table_label' => '사용자',
+            ]), [
+                ['field_key' => 'name', 'field_name' => '이름', 'field_type' => 'textbox', 'is_required' => true, 'is_seed_default' => true, 'order_no' => 1],
+                ['field_key' => 'email', 'field_name' => '이메일', 'field_type' => 'textbox', 'is_required' => true, 'is_seed_default' => true, 'order_no' => 2],
+                ['field_key' => 'phone', 'field_name' => '전화번호', 'field_type' => 'textbox', 'is_required' => false, 'is_seed_default' => true, 'order_no' => 3],
+                ['field_key' => 'role', 'field_name' => '역할', 'field_type' => 'dropdown', 'is_required' => false, 'is_seed_default' => true, 'order_no' => 4],
+                ['field_key' => 'is_active', 'field_name' => '활성화', 'field_type' => 'checkbox', 'is_required' => false, 'is_seed_default' => true, 'order_no' => 5, 'default_value' => 'true'],
+                ['field_key' => 'is_super_admin', 'field_name' => '슈퍼관리자', 'field_type' => 'checkbox', 'is_required' => false, 'is_seed_default' => false, 'order_no' => 6, 'default_value' => 'false'],
+            ]),
+        ];
+
+        foreach ($definitions as $definition) {
+            SystemFieldDefinition::updateOrCreate(
+                [
+                    'source_table' => $definition['source_table'],
+                    'field_key' => $definition['field_key'],
+                ],
+                array_merge($definition, ['is_active' => true])
+            );
+        }
+
+        $this->command->info('SystemFieldDefinition 시딩 완료: ' . count($definitions) . '개');
+    }
+}