diff --git a/src/wp-includes/option.php b/src/wp-includes/option.php
index 8bd6a1821162e..67ff3596e671d 100644
--- a/src/wp-includes/option.php
+++ b/src/wp-includes/option.php
@@ -1372,6 +1372,10 @@ function wp_filter_default_autoload_value_via_option_size( $autoload, $option, $
 /**
  * Deletes a transient.
  *
+ * If an orphaned transient timeout option exists without a corresponding transient
+ * option, the timeout option is deleted, but the function returns false because
+ * no transient value option existed to be deleted.
+ *
  * @since 2.8.0
  *
  * @param string $transient Transient name. Expected to not be SQL-escaped.
@@ -1397,9 +1401,7 @@ function delete_transient( $transient ) {
 		$option         = '_transient_' . $transient;
 		$result         = delete_option( $option );
 
-		if ( $result ) {
-			delete_option( $option_timeout );
-		}
+		delete_option( $option_timeout );
 	}
 
 	if ( $result ) {
@@ -1655,6 +1657,19 @@ function delete_expired_transients( $force_db = false ) {
 		)
 	);
 
+	$wpdb->query(
+		$wpdb->prepare(
+			"DELETE a FROM {$wpdb->options} a
+			LEFT JOIN {$wpdb->options} b
+				ON b.option_name = CONCAT( '_transient_', SUBSTRING( a.option_name, 20 ) )
+			WHERE a.option_name LIKE %s
+			AND a.option_value < %d
+			AND b.option_id IS NULL",
+			$wpdb->esc_like( '_transient_timeout_' ) . '%',
+			time()
+		)
+	);
+
 	if ( ! is_multisite() ) {
 		// Single site stores site transients in the options table.
 		$wpdb->query(
@@ -1669,6 +1684,19 @@ function delete_expired_transients( $force_db = false ) {
 				time()
 			)
 		);
+
+		$wpdb->query(
+			$wpdb->prepare(
+				"DELETE a FROM {$wpdb->options} a
+				LEFT JOIN {$wpdb->options} b
+					ON b.option_name = CONCAT( '_site_transient_', SUBSTRING( a.option_name, 25 ) )
+				WHERE a.option_name LIKE %s
+				AND a.option_value < %d
+				AND b.option_id IS NULL",
+				$wpdb->esc_like( '_site_transient_timeout_' ) . '%',
+				time()
+			)
+		);
 	} elseif ( is_main_site() && is_main_network() ) {
 		// Multisite stores site transients in the sitemeta table.
 		$wpdb->query(
@@ -1677,12 +1705,27 @@ function delete_expired_transients( $force_db = false ) {
 				WHERE a.meta_key LIKE %s
 				AND a.meta_key NOT LIKE %s
 				AND b.meta_key = CONCAT( '_site_transient_timeout_', SUBSTRING( a.meta_key, 17 ) )
+				AND b.site_id = a.site_id
 				AND b.meta_value < %d",
 				$wpdb->esc_like( '_site_transient_' ) . '%',
 				$wpdb->esc_like( '_site_transient_timeout_' ) . '%',
 				time()
 			)
 		);
+
+		$wpdb->query(
+			$wpdb->prepare(
+				"DELETE a FROM {$wpdb->sitemeta} a
+				LEFT JOIN {$wpdb->sitemeta} b
+					ON b.meta_key = CONCAT( '_site_transient_', SUBSTRING( a.meta_key, 25 ) )
+					AND b.site_id = a.site_id
+				WHERE a.meta_key LIKE %s
+				AND a.meta_value < %d
+				AND b.meta_id IS NULL",
+				$wpdb->esc_like( '_site_transient_timeout_' ) . '%',
+				time()
+			)
+		);
 	}
 }
 
@@ -2503,9 +2546,13 @@ function update_network_option( $network_id, $option, $value ) {
 /**
  * Deletes a site transient.
  *
+ * If an orphaned site transient timeout option exists without a corresponding transient
+ * option, the timeout option is deleted, but the function returns false because
+ * no transient value option existed to be deleted.
+ *
  * @since 2.9.0
  *
- * @param string $transient Transient name. Expected to not be SQL-escaped.
+ * @param string $transient Site transient name. Expected to not be SQL-escaped.
  * @return bool True if the transient was deleted, false otherwise.
  */
 function delete_site_transient( $transient ) {
@@ -2528,9 +2575,7 @@ function delete_site_transient( $transient ) {
 		$option         = '_site_transient_' . $transient;
 		$result         = delete_site_option( $option );
 
-		if ( $result ) {
-			delete_site_option( $option_timeout );
-		}
+		delete_site_option( $option_timeout );
 	}
 
 	if ( $result ) {
diff --git a/tests/phpunit/tests/option/siteTransient.php b/tests/phpunit/tests/option/siteTransient.php
index daabc1edf5a97..a40bb7d10b931 100644
--- a/tests/phpunit/tests/option/siteTransient.php
+++ b/tests/phpunit/tests/option/siteTransient.php
@@ -155,4 +155,300 @@ public function test_site_transients_not_stored_in_options_table_on_ms() {
 
 		$this->assertNull( $option, 'Querying option table should not return transient on multisite.' );
 	}
+
+	/**
+	 * Tests that delete_site_transient() removes an orphaned timeout row.
+	 *
+	 * @ticket 65863
+	 */
+	public function test_delete_site_transient_removes_orphaned_timeout() {
+		$key = 'orphaned_timeout';
+
+		set_site_transient( $key, 'value', 3600 );
+
+		// Remove the value row, leaving only the timeout row.
+		delete_site_option( '_site_transient_' . $key );
+
+		$this->assertFalse( get_site_option( '_site_transient_' . $key ) );
+		$this->assertNotFalse( get_site_option( '_site_transient_timeout_' . $key ) );
+
+		delete_site_transient( $key );
+
+		$this->assertFalse( get_site_option( '_site_transient_' . $key ) );
+		$this->assertFalse( get_site_option( '_site_transient_timeout_' . $key ) );
+	}
+
+	/**
+	 * Tests that delete_expired_transients() removes expired orphaned site transient timeouts on single site.
+	 *
+	 * @ticket 65863
+	 * @group ms-excluded
+	 *
+	 * @covers ::delete_expired_transients
+	 */
+	public function test_delete_expired_site_transients_orphaned_timeouts_single_site() {
+		global $wpdb;
+
+		$now = time();
+
+		// Expired orphaned timeout (should be deleted).
+		$wpdb->query(
+			$wpdb->prepare(
+				"INSERT INTO {$wpdb->options} (option_name, option_value, autoload) VALUES (%s, %s, 'no')",
+				'_site_transient_timeout_expired_orphan',
+				$now - 100
+			)
+		);
+
+		// Unexpired orphaned timeout (should be kept).
+		$wpdb->query(
+			$wpdb->prepare(
+				"INSERT INTO {$wpdb->options} (option_name, option_value, autoload) VALUES (%s, %s, 'no')",
+				'_site_transient_timeout_unexpired_orphan',
+				$now + 100
+			)
+		);
+
+		// Expired pair (should be deleted).
+		$wpdb->query(
+			$wpdb->prepare(
+				"INSERT INTO {$wpdb->options} (option_name, option_value, autoload) VALUES (%s, %s, 'no')",
+				'_site_transient_expired_pair',
+				'value'
+			)
+		);
+		$wpdb->query(
+			$wpdb->prepare(
+				"INSERT INTO {$wpdb->options} (option_name, option_value, autoload) VALUES (%s, %s, 'no')",
+				'_site_transient_timeout_expired_pair',
+				$now - 100
+			)
+		);
+
+		// Unexpired pair (should be kept).
+		$wpdb->query(
+			$wpdb->prepare(
+				"INSERT INTO {$wpdb->options} (option_name, option_value, autoload) VALUES (%s, %s, 'no')",
+				'_site_transient_unexpired_pair',
+				'value'
+			)
+		);
+		$wpdb->query(
+			$wpdb->prepare(
+				"INSERT INTO {$wpdb->options} (option_name, option_value, autoload) VALUES (%s, %s, 'no')",
+				'_site_transient_timeout_unexpired_pair',
+				$now + 100
+			)
+		);
+
+		delete_expired_transients( true );
+
+		$this->assertNull(
+			$wpdb->get_var( "SELECT option_value FROM {$wpdb->options} WHERE option_name = '_site_transient_timeout_expired_orphan'" ),
+			'Expired orphan site transient timeout should be deleted.'
+		);
+		$this->assertNotNull(
+			$wpdb->get_var( "SELECT option_value FROM {$wpdb->options} WHERE option_name = '_site_transient_timeout_unexpired_orphan'" ),
+			'Unexpired orphan site transient timeout should be retained.'
+		);
+
+		$this->assertNull(
+			$wpdb->get_var( "SELECT option_value FROM {$wpdb->options} WHERE option_name = '_site_transient_expired_pair'" ),
+			'Expired site transient value should be deleted.'
+		);
+		$this->assertNull(
+			$wpdb->get_var( "SELECT option_value FROM {$wpdb->options} WHERE option_name = '_site_transient_timeout_expired_pair'" ),
+			'Expired site transient timeout should be deleted.'
+		);
+
+		$this->assertSame(
+			'value',
+			$wpdb->get_var( "SELECT option_value FROM {$wpdb->options} WHERE option_name = '_site_transient_unexpired_pair'" ),
+			'Unexpired site transient value should be retained.'
+		);
+		$this->assertNotNull(
+			$wpdb->get_var( "SELECT option_value FROM {$wpdb->options} WHERE option_name = '_site_transient_timeout_unexpired_pair'" ),
+			'Unexpired site transient timeout should be retained.'
+		);
+	}
+
+	/**
+	 * Tests that delete_expired_transients() removes expired orphaned site transient timeouts on multisite.
+	 *
+	 * @ticket 65863
+	 * @group ms-required
+	 *
+	 * @covers ::delete_expired_transients
+	 */
+	public function test_delete_expired_site_transients_orphaned_timeouts_multisite() {
+		global $wpdb;
+
+		$now     = time();
+		$site_id = get_current_network_id();
+
+		// Expired orphaned timeout (should be deleted).
+		$wpdb->query(
+			$wpdb->prepare(
+				"INSERT INTO {$wpdb->sitemeta} (site_id, meta_key, meta_value) VALUES (%d, %s, %s)",
+				$site_id,
+				'_site_transient_timeout_expired_orphan',
+				$now - 100
+			)
+		);
+
+		// Unexpired orphaned timeout (should be kept).
+		$wpdb->query(
+			$wpdb->prepare(
+				"INSERT INTO {$wpdb->sitemeta} (site_id, meta_key, meta_value) VALUES (%d, %s, %s)",
+				$site_id,
+				'_site_transient_timeout_unexpired_orphan',
+				$now + 100
+			)
+		);
+
+		// Expired pair (should be deleted).
+		$wpdb->query(
+			$wpdb->prepare(
+				"INSERT INTO {$wpdb->sitemeta} (site_id, meta_key, meta_value) VALUES (%d, %s, %s)",
+				$site_id,
+				'_site_transient_expired_pair',
+				'value'
+			)
+		);
+		$wpdb->query(
+			$wpdb->prepare(
+				"INSERT INTO {$wpdb->sitemeta} (site_id, meta_key, meta_value) VALUES (%d, %s, %s)",
+				$site_id,
+				'_site_transient_timeout_expired_pair',
+				$now - 100
+			)
+		);
+
+		// Unexpired pair (should be kept).
+		$wpdb->query(
+			$wpdb->prepare(
+				"INSERT INTO {$wpdb->sitemeta} (site_id, meta_key, meta_value) VALUES (%d, %s, %s)",
+				$site_id,
+				'_site_transient_unexpired_pair',
+				'value'
+			)
+		);
+		$wpdb->query(
+			$wpdb->prepare(
+				"INSERT INTO {$wpdb->sitemeta} (site_id, meta_key, meta_value) VALUES (%d, %s, %s)",
+				$site_id,
+				'_site_transient_timeout_unexpired_pair',
+				$now + 100
+			)
+		);
+
+		delete_expired_transients( true );
+
+		$this->assertNull(
+			$wpdb->get_var( "SELECT meta_value FROM {$wpdb->sitemeta} WHERE meta_key = '_site_transient_timeout_expired_orphan'" ),
+			'Expired orphan site transient timeout should be deleted in multisite.'
+		);
+		$this->assertNotNull(
+			$wpdb->get_var( "SELECT meta_value FROM {$wpdb->sitemeta} WHERE meta_key = '_site_transient_timeout_unexpired_orphan'" ),
+			'Unexpired orphan site transient timeout should be retained in multisite.'
+		);
+
+		$this->assertNull(
+			$wpdb->get_var( "SELECT meta_value FROM {$wpdb->sitemeta} WHERE meta_key = '_site_transient_expired_pair'" ),
+			'Expired site transient value should be deleted in multisite.'
+		);
+		$this->assertNull(
+			$wpdb->get_var( "SELECT meta_value FROM {$wpdb->sitemeta} WHERE meta_key = '_site_transient_timeout_expired_pair'" ),
+			'Expired site transient timeout should be deleted in multisite.'
+		);
+
+		$this->assertSame(
+			'value',
+			$wpdb->get_var( "SELECT meta_value FROM {$wpdb->sitemeta} WHERE meta_key = '_site_transient_unexpired_pair'" ),
+			'Unexpired site transient value should be retained in multisite.'
+		);
+		$this->assertNotNull(
+			$wpdb->get_var( "SELECT meta_value FROM {$wpdb->sitemeta} WHERE meta_key = '_site_transient_timeout_unexpired_pair'" ),
+			'Unexpired site transient timeout should be retained in multisite.'
+		);
+	}
+
+	/**
+	 * Tests that delete_expired_transients() does not delete transient rows belonging to other networks.
+	 *
+	 * @ticket 65863
+	 * @ticket 65969
+	 * @group ms-required
+	 *
+	 * @covers ::delete_expired_transients
+	 */
+	public function test_delete_expired_site_transients_does_not_affect_other_networks() {
+		global $wpdb;
+
+		$now       = time();
+		$network_1 = get_current_network_id();
+		$network_2 = self::factory()->network->create();
+
+		// Network 1: Unexpired Valid Pair (should be kept).
+		$wpdb->query(
+			$wpdb->prepare(
+				"INSERT INTO {$wpdb->sitemeta} (site_id, meta_key, meta_value) VALUES (%d, %s, %s)",
+				$network_1,
+				'_site_transient_crossnet',
+				'value'
+			)
+		);
+		$wpdb->query(
+			$wpdb->prepare(
+				"INSERT INTO {$wpdb->sitemeta} (site_id, meta_key, meta_value) VALUES (%d, %s, %s)",
+				$network_1,
+				'_site_transient_timeout_crossnet',
+				$now + 3600
+			)
+		);
+
+		// Network 2: Expired Orphaned Timeout (should be deleted).
+		$wpdb->query(
+			$wpdb->prepare(
+				"INSERT INTO {$wpdb->sitemeta} (site_id, meta_key, meta_value) VALUES (%d, %s, %s)",
+				$network_2,
+				'_site_transient_timeout_crossnet',
+				$now - 100
+			)
+		);
+
+		delete_expired_transients( true );
+
+		// Network 2's expired orphan timeout should be deleted.
+		$this->assertNull(
+			$wpdb->get_var(
+				$wpdb->prepare(
+					"SELECT meta_value FROM {$wpdb->sitemeta} WHERE site_id = %d AND meta_key = '_site_transient_timeout_crossnet'",
+					$network_2
+				)
+			),
+			"Network 2's expired orphan timeout should be deleted."
+		);
+
+		// Network 1's valid pair must remain completely untouched!
+		$this->assertSame(
+			'value',
+			$wpdb->get_var(
+				$wpdb->prepare(
+					"SELECT meta_value FROM {$wpdb->sitemeta} WHERE site_id = %d AND meta_key = '_site_transient_crossnet'",
+					$network_1
+				)
+			),
+			"Network 1's valid transient value should be retained."
+		);
+		$this->assertNotNull(
+			$wpdb->get_var(
+				$wpdb->prepare(
+					"SELECT meta_value FROM {$wpdb->sitemeta} WHERE site_id = %d AND meta_key = '_site_transient_timeout_crossnet'",
+					$network_1
+				)
+			),
+			"Network 1's unexpired transient timeout should be retained."
+		);
+	}
 }
diff --git a/tests/phpunit/tests/option/transient.php b/tests/phpunit/tests/option/transient.php
index d4f6c6ce43ae9..07620844f9b38 100644
--- a/tests/phpunit/tests/option/transient.php
+++ b/tests/phpunit/tests/option/transient.php
@@ -265,4 +265,135 @@ public function test_nonexistent_key_old_timeout() {
 		);
 		$this->assertSame( $expected, $a->get_events() );
 	}
+
+	/**
+	 * Tests that delete_transient() removes an orphaned timeout row.
+	 *
+	 * @ticket 65863
+	 */
+	public function test_delete_transient_removes_orphaned_timeout() {
+		$key = 'orphaned_timeout';
+
+		set_transient( $key, 'value', 3600 );
+
+		// Remove the value row, leaving only the timeout row.
+		delete_option( '_transient_' . $key );
+
+		$this->assertFalse( get_option( '_transient_' . $key ) );
+		$this->assertNotFalse( get_option( '_transient_timeout_' . $key ) );
+
+		delete_transient( $key );
+
+		$this->assertFalse( get_option( '_transient_' . $key ) );
+		$this->assertFalse( get_option( '_transient_timeout_' . $key ) );
+	}
+
+	/**
+	 * Tests that delete_expired_transients() removes expired orphaned timeouts
+	 * while leaving unexpired orphaned timeouts, unexpired transients, and timeout-less transients intact.
+	 *
+	 * @ticket 65863
+	 *
+	 * @covers ::delete_expired_transients
+	 */
+	public function test_delete_expired_transients_with_orphaned_timeouts() {
+		global $wpdb;
+
+		$now = time();
+
+		// 1. Expired orphaned timeout (should be deleted).
+		$wpdb->query(
+			$wpdb->prepare(
+				"INSERT INTO {$wpdb->options} (option_name, option_value, autoload) VALUES (%s, %s, 'no')",
+				'_transient_timeout_expired_orphan',
+				$now - 100
+			)
+		);
+
+		// 2. Unexpired orphaned timeout (should be kept).
+		$wpdb->query(
+			$wpdb->prepare(
+				"INSERT INTO {$wpdb->options} (option_name, option_value, autoload) VALUES (%s, %s, 'no')",
+				'_transient_timeout_unexpired_orphan',
+				$now + 100
+			)
+		);
+
+		// 3. Expired pair (should be deleted).
+		$wpdb->query(
+			$wpdb->prepare(
+				"INSERT INTO {$wpdb->options} (option_name, option_value, autoload) VALUES (%s, %s, 'no')",
+				'_transient_expired_pair',
+				'value'
+			)
+		);
+		$wpdb->query(
+			$wpdb->prepare(
+				"INSERT INTO {$wpdb->options} (option_name, option_value, autoload) VALUES (%s, %s, 'no')",
+				'_transient_timeout_expired_pair',
+				$now - 100
+			)
+		);
+
+		// 4. Unexpired pair (should be kept).
+		$wpdb->query(
+			$wpdb->prepare(
+				"INSERT INTO {$wpdb->options} (option_name, option_value, autoload) VALUES (%s, %s, 'no')",
+				'_transient_unexpired_pair',
+				'value'
+			)
+		);
+		$wpdb->query(
+			$wpdb->prepare(
+				"INSERT INTO {$wpdb->options} (option_name, option_value, autoload) VALUES (%s, %s, 'no')",
+				'_transient_timeout_unexpired_pair',
+				$now + 100
+			)
+		);
+
+		// 5. Value without timeout (should be kept).
+		$wpdb->query(
+			$wpdb->prepare(
+				"INSERT INTO {$wpdb->options} (option_name, option_value, autoload) VALUES (%s, %s, 'no')",
+				'_transient_no_timeout',
+				'value'
+			)
+		);
+
+		delete_expired_transients( true );
+
+		$this->assertNull(
+			$wpdb->get_var( "SELECT option_value FROM {$wpdb->options} WHERE option_name = '_transient_timeout_expired_orphan'" ),
+			'Expired orphan timeout should be deleted.'
+		);
+		$this->assertNotNull(
+			$wpdb->get_var( "SELECT option_value FROM {$wpdb->options} WHERE option_name = '_transient_timeout_unexpired_orphan'" ),
+			'Unexpired orphan timeout should be retained.'
+		);
+
+		$this->assertNull(
+			$wpdb->get_var( "SELECT option_value FROM {$wpdb->options} WHERE option_name = '_transient_expired_pair'" ),
+			'Expired transient value should be deleted.'
+		);
+		$this->assertNull(
+			$wpdb->get_var( "SELECT option_value FROM {$wpdb->options} WHERE option_name = '_transient_timeout_expired_pair'" ),
+			'Expired transient timeout should be deleted.'
+		);
+
+		$this->assertSame(
+			'value',
+			$wpdb->get_var( "SELECT option_value FROM {$wpdb->options} WHERE option_name = '_transient_unexpired_pair'" ),
+			'Unexpired transient value should be retained.'
+		);
+		$this->assertNotNull(
+			$wpdb->get_var( "SELECT option_value FROM {$wpdb->options} WHERE option_name = '_transient_timeout_unexpired_pair'" ),
+			'Unexpired transient timeout should be retained.'
+		);
+
+		$this->assertSame(
+			'value',
+			$wpdb->get_var( "SELECT option_value FROM {$wpdb->options} WHERE option_name = '_transient_no_timeout'" ),
+			'Transient without timeout should be retained.'
+		);
+	}
 }