diff --git a/dsl-template/src/commonMain/kotlin/aggregation/AggregationOperators.kt b/dsl-template/src/commonMain/kotlin/aggregation/AggregationOperators.kt
--- a/dsl-template/src/commonMain/kotlin/aggregation/AggregationOperators.kt
+++ b/dsl-template/src/commonMain/kotlin/aggregation/AggregationOperators.kt
@@ -139,6 +139,7 @@
  * Date and time operators:
  * - [`$dayOfMonth`][DateTimeValueOperators.dayOfMonth]
  * - [`$dayOfWeek`][DateTimeValueOperators.dayOfWeek]
+ * - [`$dayOfYear`][DateTimeValueOperators.dayOfYear]
  * - [`$hour`][DateTimeValueOperators.hour]
  * - [`$isoDayOfWeek`][DateTimeValueOperators.dayOfWeekIso]
  * - [`$isoWeek`][DateTimeValueOperators.weekIso]
diff --git a/dsl/src/commonMain/kotlin/aggregation/AggregationOperators.kt b/dsl/src/commonMain/kotlin/aggregation/AggregationOperators.kt
--- a/dsl/src/commonMain/kotlin/aggregation/AggregationOperators.kt
+++ b/dsl/src/commonMain/kotlin/aggregation/AggregationOperators.kt
@@ -142,6 +142,7 @@
  * Date and time operators:
  * - [`$dayOfMonth`][DateTimeValueOperators.dayOfMonth]
  * - [`$dayOfWeek`][DateTimeValueOperators.dayOfWeek]
+ * - [`$dayOfYear`][DateTimeValueOperators.dayOfYear]
  * - [`$hour`][DateTimeValueOperators.hour]
  * - [`$isoDayOfWeek`][DateTimeValueOperators.dayOfWeekIso]
  * - [`$isoWeek`][DateTimeValueOperators.weekIso]
diff --git a/dsl-template/src/commonMain/kotlin/aggregation/operators/DateTimeValueOperators.kt b/dsl-template/src/commonMain/kotlin/aggregation/operators/DateTimeValueOperators.kt
--- a/dsl-template/src/commonMain/kotlin/aggregation/operators/DateTimeValueOperators.kt
+++ b/dsl-template/src/commonMain/kotlin/aggregation/operators/DateTimeValueOperators.kt
@@ -1210,6 +1210,107 @@
 
 	// endregion
 
+	// region $dayOfYear
+
+	/**
+	 * Returns the day of the year for a date as a number between `1` and `366`.
+	 *
+	 * The year starts on January 1st, so January 1st is day `1`, and December 31st is day `365` (or `366` in a leap year).
+	 *
+	 * The accepted date types are [Instant], [ObjectId] and [Timestamp].
+	 *
+	 * ### Example
+	 *
+	 * ```kotlin
+	 * class User(
+	 *     val name: String,
+	 *     val birthdate: Instant,
+	 *     val birthdayOfYear: Int? = null,
+	 * )
+	 *
+	 * users.updateManyWithPipeline {
+	 *     set {
+	 *         User::birthdayOfYear set User::birthdate.dayOfYear
+	 *     }
+	 * }
+	 * ```
+	 *
+	 * ### External resources
+	 *
+	 * - [Official documentation](https://www.mongodb.com/docs/manual/reference/operator/aggregation/dayOfYear/)
+	 */
+	@OptIn(LowLevelApi::class)
+	val <R : Any> Value<R, Instant>.dayOfYear: Value<R, Int>
+		get() = UnaryOperator(context, "dayOfYear", this)
+
+	/**
+	 * Returns the day of the year for a date as a number between `1` and `366`.
+	 *
+	 * The year starts on January 1st, so January 1st is day `1`, and December 31st is day `365` (or `366` in a leap year).
+	 *
+	 * The accepted date types are [Instant], [ObjectId] and [Timestamp].
+	 *
+	 * ### Example
+	 *
+	 * ```kotlin
+	 * class User(
+	 *     val name: String,
+	 *     val birthdate: Instant,
+	 *     val birthdayOfYear: Int? = null,
+	 * )
+	 *
+	 * users.updateManyWithPipeline {
+	 *     set {
+	 *         User::birthdayOfYear set User::birthdate.dayOfYear
+	 *     }
+	 * }
+	 * ```
+	 *
+	 * ### External resources
+	 *
+	 * - [Official documentation](https://www.mongodb.com/docs/manual/reference/operator/aggregation/dayOfYear/)
+	 */
+	@OptIn(LowLevelApi::class)
+	@Suppress("WRONG_MODIFIER_CONTAINING_DECLARATION")
+	@get:JvmName("dayOfYearOfObjectId")
+	final val <R : Any> Value<R, ObjectId>.dayOfYear: Value<R, Int>
+		get() = UnaryOperator(context, "dayOfYear", this)
+
+	/**
+	 * Returns the day of the year for a date as a number between `1` and `366`.
+	 *
+	 * The year starts on January 1st, so January 1st is day `1`, and December 31st is day `365` (or `366` in a leap year).
+	 *
+	 * The accepted date types are [Instant], [ObjectId] and [Timestamp].
+	 *
+	 * ### Example
+	 *
+	 * ```kotlin
+	 * class User(
+	 *     val name: String,
+	 *     val birthdate: Instant,
+	 *     val birthdayOfYear: Int? = null,
+	 * )
+	 *
+	 * users.updateManyWithPipeline {
+	 *     set {
+	 *         User::birthdayOfYear set User::birthdate.dayOfYear
+	 *     }
+	 * }
+	 * ```
+	 *
+	 * ### External resources
+	 *
+	 * - [Official documentation](https://www.mongodb.com/docs/manual/reference/operator/aggregation/dayOfYear/)
+	 */
+	@OptIn(LowLevelApi::class)
+	@Suppress("WRONG_MODIFIER_CONTAINING_DECLARATION")
+	@get:JvmName("dayOfYearOfTimestamp")
+	final val <R : Any> Value<R, Timestamp>.dayOfYear: Value<R, Int>
+		get() = UnaryOperator(context, "dayOfYear", this)
+
+	// endregion
+
 	@LowLevelApi
 	private class UnaryOperator<Root : Any, Input, Output>(
 		context: BsonContext,
diff --git a/dsl/src/commonMain/kotlin/aggregation/operators/DateTimeValueOperators.kt b/dsl/src/commonMain/kotlin/aggregation/operators/DateTimeValueOperators.kt
--- a/dsl/src/commonMain/kotlin/aggregation/operators/DateTimeValueOperators.kt
+++ b/dsl/src/commonMain/kotlin/aggregation/operators/DateTimeValueOperators.kt
@@ -4672,6 +4672,402 @@
 
 	// endregion
 
+	// region $dayOfYear
+
+	/**
+	 * Returns the day of the year for a date as a number between `1` and `366`.
+	 *
+	 * The year starts on January 1st, so January 1st is day `1`, and December 31st is day `365` (or `366` in a leap year).
+	 *
+	 * The accepted date types are [Instant], [ObjectId] and [Timestamp].
+	 *
+	 * ### Example
+	 *
+	 * ```kotlin
+	 * class User(
+	 *     val name: String,
+	 *     val birthdate: Instant,
+	 *     val birthdayOfYear: Int? = null,
+	 * )
+	 *
+	 * users.updateManyWithPipeline {
+	 *     set {
+	 *         User::birthdayOfYear set User::birthdate.dayOfYear
+	 *     }
+	 * }
+	 * ```
+	 *
+	 * ### External resources
+	 *
+	 * - [Official documentation](https://www.mongodb.com/docs/manual/reference/operator/aggregation/dayOfYear/)
+	 */
+	@OptIn(LowLevelApi::class)
+	val <R : Any> Value<R, Instant>.dayOfYear: Value<R, Int>
+		get() = UnaryOperator(context, "dayOfYear", this)
+
+	/**
+	 * Returns the day of the year for a date as a number between `1` and `366`.
+	 *
+	 * The year starts on January 1st, so January 1st is day `1`, and December 31st is day `365` (or `366` in a leap year).
+	 *
+	 * The accepted date types are [Instant], [ObjectId] and [Timestamp].
+	 *
+	 * ### Example
+	 *
+	 * ```kotlin
+	 * class User(
+	 *     val name: String,
+	 *     val birthdate: Instant,
+	 *     val birthdayOfYear: Int? = null,
+	 * )
+	 *
+	 * users.updateManyWithPipeline {
+	 *     set {
+	 *         User::birthdayOfYear set User::birthdate.dayOfYear
+	 *     }
+	 * }
+	 * ```
+	 *
+	 * ### External resources
+	 *
+	 * - [Official documentation](https://www.mongodb.com/docs/manual/reference/operator/aggregation/dayOfYear/)
+	 */
+	@OptIn(LowLevelApi::class)
+	val <R : Any> opensavvy.ktmongo.dsl.path.Field<R, Instant>.dayOfYear: Value<R, Int>
+		get() = of(this).dayOfYear
+
+	/**
+	 * Returns the day of the year for a date as a number between `1` and `366`.
+	 *
+	 * The year starts on January 1st, so January 1st is day `1`, and December 31st is day `365` (or `366` in a leap year).
+	 *
+	 * The accepted date types are [Instant], [ObjectId] and [Timestamp].
+	 *
+	 * ### Example
+	 *
+	 * ```kotlin
+	 * class User(
+	 *     val name: String,
+	 *     val birthdate: Instant,
+	 *     val birthdayOfYear: Int? = null,
+	 * )
+	 *
+	 * users.updateManyWithPipeline {
+	 *     set {
+	 *         User::birthdayOfYear set User::birthdate.dayOfYear
+	 *     }
+	 * }
+	 * ```
+	 *
+	 * ### External resources
+	 *
+	 * - [Official documentation](https://www.mongodb.com/docs/manual/reference/operator/aggregation/dayOfYear/)
+	 */
+	@OptIn(LowLevelApi::class)
+	val <R : Any> kotlin.reflect.KProperty1<R, Instant>.dayOfYear: Value<R, Int>
+		get() = of(this).dayOfYear
+
+	/**
+	 * Returns the day of the year for a date as a number between `1` and `366`.
+	 *
+	 * The year starts on January 1st, so January 1st is day `1`, and December 31st is day `365` (or `366` in a leap year).
+	 *
+	 * The accepted date types are [Instant], [ObjectId] and [Timestamp].
+	 *
+	 * ### Example
+	 *
+	 * ```kotlin
+	 * class User(
+	 *     val name: String,
+	 *     val birthdate: Instant,
+	 *     val birthdayOfYear: Int? = null,
+	 * )
+	 *
+	 * users.updateManyWithPipeline {
+	 *     set {
+	 *         User::birthdayOfYear set User::birthdate.dayOfYear
+	 *     }
+	 * }
+	 * ```
+	 *
+	 * ### External resources
+	 *
+	 * - [Official documentation](https://www.mongodb.com/docs/manual/reference/operator/aggregation/dayOfYear/)
+	 */
+	@kotlin.internal.LowPriorityInOverloadResolution
+	@Suppress("INVISIBLE_REFERENCE")
+	@OptIn(LowLevelApi::class)
+	val Instant.dayOfYear: Value<Any, Int>
+		get() = of(this).dayOfYear
+
+	/**
+	 * Returns the day of the year for a date as a number between `1` and `366`.
+	 *
+	 * The year starts on January 1st, so January 1st is day `1`, and December 31st is day `365` (or `366` in a leap year).
+	 *
+	 * The accepted date types are [Instant], [ObjectId] and [Timestamp].
+	 *
+	 * ### Example
+	 *
+	 * ```kotlin
+	 * class User(
+	 *     val name: String,
+	 *     val birthdate: Instant,
+	 *     val birthdayOfYear: Int? = null,
+	 * )
+	 *
+	 * users.updateManyWithPipeline {
+	 *     set {
+	 *         User::birthdayOfYear set User::birthdate.dayOfYear
+	 *     }
+	 * }
+	 * ```
+	 *
+	 * ### External resources
+	 *
+	 * - [Official documentation](https://www.mongodb.com/docs/manual/reference/operator/aggregation/dayOfYear/)
+	 */
+	@OptIn(LowLevelApi::class)
+	@Suppress("WRONG_MODIFIER_CONTAINING_DECLARATION")
+	@get:JvmName("dayOfYearOfObjectId")
+	final val <R : Any> Value<R, ObjectId>.dayOfYear: Value<R, Int>
+		get() = UnaryOperator(context, "dayOfYear", this)
+
+	/**
+	 * Returns the day of the year for a date as a number between `1` and `366`.
+	 *
+	 * The year starts on January 1st, so January 1st is day `1`, and December 31st is day `365` (or `366` in a leap year).
+	 *
+	 * The accepted date types are [Instant], [ObjectId] and [Timestamp].
+	 *
+	 * ### Example
+	 *
+	 * ```kotlin
+	 * class User(
+	 *     val name: String,
+	 *     val birthdate: Instant,
+	 *     val birthdayOfYear: Int? = null,
+	 * )
+	 *
+	 * users.updateManyWithPipeline {
+	 *     set {
+	 *         User::birthdayOfYear set User::birthdate.dayOfYear
+	 *     }
+	 * }
+	 * ```
+	 *
+	 * ### External resources
+	 *
+	 * - [Official documentation](https://www.mongodb.com/docs/manual/reference/operator/aggregation/dayOfYear/)
+	 */
+	@OptIn(LowLevelApi::class)
+	@Suppress("WRONG_MODIFIER_CONTAINING_DECLARATION")
+	@get:JvmName("dayOfYearOfObjectId")
+	final val <R : Any> opensavvy.ktmongo.dsl.path.Field<R, ObjectId>.dayOfYear: Value<R, Int>
+		get() = of(this).dayOfYear
+
+	/**
+	 * Returns the day of the year for a date as a number between `1` and `366`.
+	 *
+	 * The year starts on January 1st, so January 1st is day `1`, and December 31st is day `365` (or `366` in a leap year).
+	 *
+	 * The accepted date types are [Instant], [ObjectId] and [Timestamp].
+	 *
+	 * ### Example
+	 *
+	 * ```kotlin
+	 * class User(
+	 *     val name: String,
+	 *     val birthdate: Instant,
+	 *     val birthdayOfYear: Int? = null,
+	 * )
+	 *
+	 * users.updateManyWithPipeline {
+	 *     set {
+	 *         User::birthdayOfYear set User::birthdate.dayOfYear
+	 *     }
+	 * }
+	 * ```
+	 *
+	 * ### External resources
+	 *
+	 * - [Official documentation](https://www.mongodb.com/docs/manual/reference/operator/aggregation/dayOfYear/)
+	 */
+	@OptIn(LowLevelApi::class)
+	@Suppress("WRONG_MODIFIER_CONTAINING_DECLARATION")
+	@get:JvmName("dayOfYearOfObjectId")
+	final val <R : Any> kotlin.reflect.KProperty1<R, ObjectId>.dayOfYear: Value<R, Int>
+		get() = of(this).dayOfYear
+
+	/**
+	 * Returns the day of the year for a date as a number between `1` and `366`.
+	 *
+	 * The year starts on January 1st, so January 1st is day `1`, and December 31st is day `365` (or `366` in a leap year).
+	 *
+	 * The accepted date types are [Instant], [ObjectId] and [Timestamp].
+	 *
+	 * ### Example
+	 *
+	 * ```kotlin
+	 * class User(
+	 *     val name: String,
+	 *     val birthdate: Instant,
+	 *     val birthdayOfYear: Int? = null,
+	 * )
+	 *
+	 * users.updateManyWithPipeline {
+	 *     set {
+	 *         User::birthdayOfYear set User::birthdate.dayOfYear
+	 *     }
+	 * }
+	 * ```
+	 *
+	 * ### External resources
+	 *
+	 * - [Official documentation](https://www.mongodb.com/docs/manual/reference/operator/aggregation/dayOfYear/)
+	 */
+	@kotlin.internal.LowPriorityInOverloadResolution
+	@OptIn(LowLevelApi::class)
+	@Suppress("INVISIBLE_REFERENCE", "WRONG_MODIFIER_CONTAINING_DECLARATION")
+	@get:JvmName("dayOfYearOfObjectId")
+	final val ObjectId.dayOfYear: Value<Any, Int>
+		get() = of(this).dayOfYear
+
+	/**
+	 * Returns the day of the year for a date as a number between `1` and `366`.
+	 *
+	 * The year starts on January 1st, so January 1st is day `1`, and December 31st is day `365` (or `366` in a leap year).
+	 *
+	 * The accepted date types are [Instant], [ObjectId] and [Timestamp].
+	 *
+	 * ### Example
+	 *
+	 * ```kotlin
+	 * class User(
+	 *     val name: String,
+	 *     val birthdate: Instant,
+	 *     val birthdayOfYear: Int? = null,
+	 * )
+	 *
+	 * users.updateManyWithPipeline {
+	 *     set {
+	 *         User::birthdayOfYear set User::birthdate.dayOfYear
+	 *     }
+	 * }
+	 * ```
+	 *
+	 * ### External resources
+	 *
+	 * - [Official documentation](https://www.mongodb.com/docs/manual/reference/operator/aggregation/dayOfYear/)
+	 */
+	@OptIn(LowLevelApi::class)
+	@Suppress("WRONG_MODIFIER_CONTAINING_DECLARATION")
+	@get:JvmName("dayOfYearOfTimestamp")
+	final val <R : Any> Value<R, Timestamp>.dayOfYear: Value<R, Int>
+		get() = UnaryOperator(context, "dayOfYear", this)
+
+	/**
+	 * Returns the day of the year for a date as a number between `1` and `366`.
+	 *
+	 * The year starts on January 1st, so January 1st is day `1`, and December 31st is day `365` (or `366` in a leap year).
+	 *
+	 * The accepted date types are [Instant], [ObjectId] and [Timestamp].
+	 *
+	 * ### Example
+	 *
+	 * ```kotlin
+	 * class User(
+	 *     val name: String,
+	 *     val birthdate: Instant,
+	 *     val birthdayOfYear: Int? = null,
+	 * )
+	 *
+	 * users.updateManyWithPipeline {
+	 *     set {
+	 *         User::birthdayOfYear set User::birthdate.dayOfYear
+	 *     }
+	 * }
+	 * ```
+	 *
+	 * ### External resources
+	 *
+	 * - [Official documentation](https://www.mongodb.com/docs/manual/reference/operator/aggregation/dayOfYear/)
+	 */
+	@OptIn(LowLevelApi::class)
+	@Suppress("WRONG_MODIFIER_CONTAINING_DECLARATION")
+	@get:JvmName("dayOfYearOfTimestamp")
+	final val <R : Any> opensavvy.ktmongo.dsl.path.Field<R, Timestamp>.dayOfYear: Value<R, Int>
+		get() = of(this).dayOfYear
+
+	/**
+	 * Returns the day of the year for a date as a number between `1` and `366`.
+	 *
+	 * The year starts on January 1st, so January 1st is day `1`, and December 31st is day `365` (or `366` in a leap year).
+	 *
+	 * The accepted date types are [Instant], [ObjectId] and [Timestamp].
+	 *
+	 * ### Example
+	 *
+	 * ```kotlin
+	 * class User(
+	 *     val name: String,
+	 *     val birthdate: Instant,
+	 *     val birthdayOfYear: Int? = null,
+	 * )
+	 *
+	 * users.updateManyWithPipeline {
+	 *     set {
+	 *         User::birthdayOfYear set User::birthdate.dayOfYear
+	 *     }
+	 * }
+	 * ```
+	 *
+	 * ### External resources
+	 *
+	 * - [Official documentation](https://www.mongodb.com/docs/manual/reference/operator/aggregation/dayOfYear/)
+	 */
+	@OptIn(LowLevelApi::class)
+	@Suppress("WRONG_MODIFIER_CONTAINING_DECLARATION")
+	@get:JvmName("dayOfYearOfTimestamp")
+	final val <R : Any> kotlin.reflect.KProperty1<R, Timestamp>.dayOfYear: Value<R, Int>
+		get() = of(this).dayOfYear
+
+	/**
+	 * Returns the day of the year for a date as a number between `1` and `366`.
+	 *
+	 * The year starts on January 1st, so January 1st is day `1`, and December 31st is day `365` (or `366` in a leap year).
+	 *
+	 * The accepted date types are [Instant], [ObjectId] and [Timestamp].
+	 *
+	 * ### Example
+	 *
+	 * ```kotlin
+	 * class User(
+	 *     val name: String,
+	 *     val birthdate: Instant,
+	 *     val birthdayOfYear: Int? = null,
+	 * )
+	 *
+	 * users.updateManyWithPipeline {
+	 *     set {
+	 *         User::birthdayOfYear set User::birthdate.dayOfYear
+	 *     }
+	 * }
+	 * ```
+	 *
+	 * ### External resources
+	 *
+	 * - [Official documentation](https://www.mongodb.com/docs/manual/reference/operator/aggregation/dayOfYear/)
+	 */
+	@kotlin.internal.LowPriorityInOverloadResolution
+	@OptIn(LowLevelApi::class)
+	@Suppress("INVISIBLE_REFERENCE", "WRONG_MODIFIER_CONTAINING_DECLARATION")
+	@get:JvmName("dayOfYearOfTimestamp")
+	final val Timestamp.dayOfYear: Value<Any, Int>
+		get() = of(this).dayOfYear
+
+	// endregion
+
 	@LowLevelApi
 	private class UnaryOperator<Root : Any, Input, Output>(
 		context: BsonContext,
diff --git a/dsl/src/commonTest/kotlin/aggregation/operators/DateTimeValueOperatorsTest.kt b/dsl/src/commonTest/kotlin/aggregation/operators/DateTimeValueOperatorsTest.kt
--- a/dsl/src/commonTest/kotlin/aggregation/operators/DateTimeValueOperatorsTest.kt
+++ b/dsl/src/commonTest/kotlin/aggregation/operators/DateTimeValueOperatorsTest.kt
@@ -37,6 +37,7 @@
 		val hour: Int,
 		val dayOfMonth: Int,
 		val dayOfWeek: Int,
+		val dayOfYear: Int,
 	)
 
 	test($$"$year") {
@@ -248,6 +249,24 @@
 						"$set": {
 							"dayOfWeek": {
 								"$dayOfWeek": "$date"
+							}
+						}
+					}
+				]
+			""".trimIndent())
+	}
+
+	test($$"$dayOfYear") {
+		TestPipeline<Target>()
+			.set {
+				Target::dayOfYear set Target::date.dayOfYear
+			}
+			.shouldBeBson($$"""
+				[
+					{
+						"$set": {
+							"dayOfYear": {
+								"$dayOfYear": "$date"
 							}
 						}
 					}