diff --git a/server/models/Post.js b/server/models/Post.js
index ee79dc6..1a9e7f1 100644
--- a/server/models/Post.js
+++ b/server/models/Post.js
@@ -21,11 +21,19 @@ module.exports = (sequelize, DataTypes) => {
         userId: {
             type: DataTypes.UUID,
             allowNull: false,
-          },
+        },
     }, {
         tableName: 'posts',
         timestamps: true,
     });
-    
+
+    Post.associate = (models) => {
+        Post.belongsToMany(models.Tag, {
+            through: models.PostTag,
+            foreignKey: 'postId',
+            otherKey: 'tagId',
+        });
+    };
+
     return Post;
-}
\ No newline at end of file
+};
\ No newline at end of file
diff --git a/server/models/PostTag.js b/server/models/PostTag.js
new file mode 100644
index 0000000..bc84058
--- /dev/null
+++ b/server/models/PostTag.js
@@ -0,0 +1,30 @@
+// handle the relationship between Post and Tag
+// Purely join table
+
+module.exports = (sequelize, DataTypes) => {
+    const PostTag = sequelize.define("PostTag", {
+        postId: {
+            type: DataTypes.UUID,
+            allowNull: false,
+            references: {
+                model: 'posts', // refers to table name
+                key: 'id'
+            },
+            onDelete: 'CASCADE',
+        },
+        tagId: {
+            type: DataTypes.UUID,
+            allowNull: false,
+            references: {
+                model: 'tags', // refers to table name
+                key: 'id'
+            },
+            onDelete: 'CASCADE',
+        },
+    }, {
+        tableName: 'post_tags',
+        timestamps: false,
+    });
+
+    return PostTag;
+};
\ No newline at end of file
diff --git a/server/models/Tag.js b/server/models/Tag.js
new file mode 100644
index 0000000..31bf177
--- /dev/null
+++ b/server/models/Tag.js
@@ -0,0 +1,28 @@
+module.exports = (sequelize, DataTypes) => {
+    const Tag = sequelize.define("Tag", {
+        id: {
+            type: DataTypes.UUID,
+            defaultValue: DataTypes.UUIDV4,
+            allowNull: false,
+            primaryKey: true,
+        },
+        tag: {
+            type: DataTypes.STRING(30),
+            allowNull: false,
+            unique: true,  // Ensure tags are unique
+        },
+    }, {
+        tableName: 'tags',
+        timestamps: false,
+    });
+
+    Tag.associate = (models) => {
+        Tag.belongsToMany(models.Post, {
+            through: models.PostTag,
+            foreignKey: 'tagId',
+            otherKey: 'postId',
+        });
+    };
+
+    return Tag;
+};
\ No newline at end of file