diff --git a/src/Model/Definition.ts b/src/Model/Definition.ts
index b727bac..71daac9 100644
--- a/src/Model/Definition.ts
+++ b/src/Model/Definition.ts
@@ -28,7 +28,7 @@ export class Definition<SerializedType, SharkitekType>
  * @param type - The model property type.
  * @param options - Property definition options.
  */
-export function SDefine<SerializedType, SharkitekType>(type: Type<SerializedType, SharkitekType>, options: DefinitionOptions<SerializedType, SharkitekType> = {})
+export function SDefine<SerializedType, SharkitekType>(type: Type<SerializedType, SharkitekType>, options: DefinitionOptions<SerializedType, SharkitekType> = {}): Definition<SerializedType, SharkitekType>
 {
-	return new Definition(type, options);
+	return new Definition<SerializedType, SharkitekType>(type, options);
 }
diff --git a/src/Model/Types/ArrayType.ts b/src/Model/Types/ArrayType.ts
index b717d9a..2dfe381 100644
--- a/src/Model/Types/ArrayType.ts
+++ b/src/Model/Types/ArrayType.ts
@@ -6,7 +6,7 @@ import {Type} from "./Type";
 export class ArrayType<SerializedValueType, SharkitekValueType> extends Type<SerializedValueType[], SharkitekValueType[]>
 {
 	/**
-	 * Constructs a new array type of Sharkitek model property.
+	 * Constructs a new array type of a Sharkitek model property.
 	 * @param valueType - Type of the array values.
 	 */
 	constructor(protected valueType: Type<SerializedValueType, SharkitekValueType>)
diff --git a/src/Model/Types/ObjectType.ts b/src/Model/Types/ObjectType.ts
new file mode 100644
index 0000000..22c85fb
--- /dev/null
+++ b/src/Model/Types/ObjectType.ts
@@ -0,0 +1,77 @@
+import {Type} from "./Type";
+import {Definition} from "../Definition";
+
+/**
+ * Type of a simple object.
+ */
+export class ObjectType<Keys extends symbol|string> extends Type<Record<Keys, any>, Record<Keys, any>>
+{
+	/**
+	 * Constructs a new object type of a Sharkitek model property.
+	 * @param fieldsTypes Object fields types.
+	 */
+	constructor(protected fieldsTypes: Record<Keys, Definition<unknown, unknown>>)
+	{
+		super();
+	}
+
+	deserialize(value: Record<Keys, any>): Record<Keys, any>
+	{
+		if (value === undefined) return undefined;
+		if (value === null) return null;
+
+		return Object.fromEntries(
+			// For each defined field, deserialize its value according to its type.
+			(Object.entries(this.fieldsTypes) as [Keys, Definition<any, any>][]).map(([fieldName, fieldDefinition]) => (
+				// Return an entry with the current field name and the deserialized value.
+				[fieldName, fieldDefinition.type.deserialize(value[fieldName])]
+			))
+		) as Record<Keys, any>;
+	}
+
+	serialize(value: Record<Keys, any>): Record<Keys, any>
+	{
+		if (value === undefined) return undefined;
+		if (value === null) return null;
+
+		return Object.fromEntries(
+			// For each defined field, serialize its value according to its type.
+			(Object.entries(this.fieldsTypes) as [Keys, Definition<any, any>][]).map(([fieldName, fieldDefinition]) => (
+				// Return an entry with the current field name and the serialized value.
+				[fieldName, fieldDefinition.type.serialize(value[fieldName])]
+			))
+		) as Record<Keys, any>;
+	}
+
+	serializeDiff(value: Record<Keys, any>): Record<Keys, any>
+	{
+		if (value === undefined) return undefined;
+		if (value === null) return null;
+
+		return Object.fromEntries(
+			// For each defined field, serialize its diff value according to its type.
+			(Object.entries(this.fieldsTypes) as [Keys, Definition<any, any>][]).map(([fieldName, fieldDefinition]) => (
+				// Return an entry with the current field name and the serialized diff value.
+				[fieldName, fieldDefinition.type.serializeDiff(value[fieldName])]
+			))
+		) as Record<Keys, any>;
+	}
+
+	resetDiff(value: Record<Keys, any>): void
+	{
+		// For each field, reset its diff.
+		(Object.entries(this.fieldsTypes) as [Keys, Definition<any, any>][]).forEach(([fieldName, fieldDefinition]) => {
+			// Reset diff of the current field.
+			fieldDefinition.type.resetDiff(value[fieldName]);
+		});
+	}
+}
+
+/**
+ * Type of a simple object.
+ * @param fieldsTypes Object fields types.
+ */
+export function SObject<Keys extends symbol|string>(fieldsTypes: Record<Keys, Definition<unknown, unknown>>): ObjectType<Keys>
+{
+	return new ObjectType<Keys>(fieldsTypes);
+}
diff --git a/src/index.ts b/src/index.ts
index fa04563..db9c7c5 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -10,4 +10,5 @@ export * from "./Model/Types/DateType";
 export * from "./Model/Types/DecimalType";
 export * from "./Model/Types/ModelType";
 export * from "./Model/Types/NumericType";
+export * from "./Model/Types/ObjectType";
 export * from "./Model/Types/StringType";
diff --git a/tests/Model.test.ts b/tests/Model.test.ts
index a5a4112..e29da48 100644
--- a/tests/Model.test.ts
+++ b/tests/Model.test.ts
@@ -10,6 +10,7 @@ import {
 	ModelDefinition,
 	SDefine, ModelIdentifier
 } from "../src";
+import {SObject} from "../src/Model/Types/ObjectType";
 
 /**
  * Another test model.
@@ -54,6 +55,9 @@ class Article extends Model<Article>
 	authors: Author[] = [];
 	text: string;
 	evaluation: number;
+	tags: {
+		name: string;
+	}[];
 
 	protected SIdentifier(): ModelIdentifier<Article>
 	{
@@ -68,6 +72,11 @@ class Article extends Model<Article>
 			authors: SDefine(SArray(SModel(Author))),
 			text: SDefine(SString),
 			evaluation: SDefine(SDecimal),
+			tags: SDefine(SArray(
+				SObject({
+					name: SDefine(SString),
+				})
+			)),
 		};
 	}
 }
@@ -82,6 +91,7 @@ it("deserialize", () => {
 		],
 		text: "this is a long test.",
 		evaluation: "25.23",
+		tags: [ {name: "test"}, {name: "foo"} ],
 	}).serialize()).toStrictEqual({
 		id: 1,
 		title: "this is a test",
@@ -91,6 +101,7 @@ it("deserialize", () => {
 		],
 		text: "this is a long test.",
 		evaluation: "25.23",
+		tags: [ {name: "test"}, {name: "foo"} ],
 	});
 });
 
@@ -104,6 +115,9 @@ it("create and check state then serialize", () => {
 	];
 	article.text = "this is a long test.";
 	article.evaluation = 25.23;
+	article.tags = [];
+	article.tags.push({name: "test"});
+	article.tags.push({name: "foo"});
 
 	expect(article.isNew()).toBeTruthy();
 	expect(article.getIdentifier()).toStrictEqual(1);
@@ -116,6 +130,7 @@ it("create and check state then serialize", () => {
 		],
 		text: "this is a long test.",
 		evaluation: "25.23",
+		tags: [ {name: "test"}, {name: "foo"} ],
 	});
 });
 
@@ -130,6 +145,7 @@ it("deserialize then save", () => {
 		],
 		text: "this is a long test.",
 		evaluation: "25.23",
+		tags: [ {name: "test"}, {name: "foo"} ],
 	});
 
 	expect(article.isNew()).toBeFalsy();
@@ -156,6 +172,7 @@ it("save with modified submodels", () => {
 		],
 		text: "this is a long test.",
 		evaluation: "25.23",
+		tags: [ {name: "test"}, {name: "foo"} ],
 	});
 
 	article.authors = article.authors.map((author) => {