diff --git a/modules/production/ir.py b/modules/production/ir.py
index 4caba21423..f4044cc99d 100644
--- a/modules/production/ir.py
+++ b/modules/production/ir.py
@@ -1,6 +1,7 @@
 # This file is part of Tryton.  The COPYRIGHT file at the top level of
 # this repository contains the full copyright notices and license terms.
 from trytond.pool import PoolMeta
+from trytond.transaction import Transaction
 
 
 class Cron(metaclass=PoolMeta):
@@ -12,5 +13,16 @@ class Cron(metaclass=PoolMeta):
         cls.method.selection.extend([
                 ('production|set_cost_from_moves', "Set Cost from Moves"),
                 ('production|reschedule', "Reschedule Productions"),
-                ('production|assign_cron', "Assign Productions"),
                 ])
+
+    @classmethod
+    def __register__(cls, module):
+        table = cls.__table__()
+        cursor = Transaction().connection.cursor()
+
+        super().__register__(module)
+
+        # Migration from 7.0: replace assign_cron
+        cursor.execute(*table.update(
+                [table.method], ['ir.cron|stock_shipment_assign_try'],
+                where=table.method == 'production|assign_cron'))
diff --git a/modules/stock/CHANGELOG b/modules/stock/CHANGELOG
index 2d0d8e2cab..4c0edcc965 100644
--- a/modules/stock/CHANGELOG
+++ b/modules/stock/CHANGELOG
@@ -1,3 +1,4 @@
+* Unify shipment assignation scheduled jobs
 * Fill shipment number only in waiting state
 * Manage assignation for customer shipment with same picking and output location
 * Add pblc argument to assign_try
diff --git a/modules/stock/ir.py b/modules/stock/ir.py
index e6b83dd701..6a9a20fd94 100644
--- a/modules/stock/ir.py
+++ b/modules/stock/ir.py
@@ -1,6 +1,13 @@
 # This file is part of Tryton.  The COPYRIGHT file at the top level of
 # this repository contains the full copyright notices and license terms.
-from trytond.pool import PoolMeta
+
+from itertools import groupby
+from operator import attrgetter
+
+from trytond.pool import Pool, PoolMeta
+from trytond.transaction import Transaction
+
+from .shipment import ShipmentAssignMixin
 
 
 class Cron(metaclass=PoolMeta):
@@ -18,8 +25,33 @@ class Cron(metaclass=PoolMeta):
                     "Reschedule Supplier Return Shipments"),
                 ('stock.shipment.internal|reschedule',
                     "Reschedule Internal Shipments"),
-                ('stock.shipment.out|assign_cron',
-                    "Assign Customer Shipments"),
-                ('stock.shipment.internal|assign_cron',
-                    "Assign Internal Shipments"),
+                ('ir.cron|stock_shipment_assign_try', "Assign Shipments"),
                 ])
+
+    @classmethod
+    def __register__(cls, module):
+        table = cls.__table__()
+        cursor = Transaction().connection.cursor()
+
+        super().__register__(module)
+
+        # Migration from 7.0: replace assign_cron
+        cursor.execute(*table.update(
+                [table.method], ['ir.cron|stock_shipment_assign_try'],
+                where=table.method.in_([
+                        'stock.shipment.out|assign_cron',
+                        'stock.shipment.internal|assign_cron',
+                        ])))
+
+    @classmethod
+    def stock_shipment_assign_try(cls):
+        pool = Pool()
+        records = []
+        for _, kls in pool.iterobject():
+            if issubclass(kls, ShipmentAssignMixin):
+                records.extend(kls.to_assign())
+
+        records.sort(key=attrgetter('assign_order_key'))
+
+        for kls, records in groupby(records, key=attrgetter('__class__')):
+            kls.assign_try(list(records))
diff --git a/modules/stock/shipment.py b/modules/stock/shipment.py
index bf38ee19db..2aa60b48fa 100644
--- a/modules/stock/shipment.py
+++ b/modules/stock/shipment.py
@@ -210,9 +210,12 @@ class ShipmentAssignMixin(ShipmentMixin):
             ]
 
     @classmethod
-    def assign_cron(cls):
-        shipments = cls.search(cls._get_assign_domain())
-        cls.assign_try(shipments)
+    def to_assign(cls):
+        return cls.search(cls._get_assign_domain())
+
+    @property
+    def assign_order_key(self):
+        return (self.planned_date, self.create_date)
 
     def get_partially_assigned(self, name):
         return (self.state != 'assigned'
diff --git a/modules/stock/tests/scenario_stock_shipment_cron_assign.rst b/modules/stock/tests/scenario_stock_shipment_cron_assign.rst
new file mode 100644
index 0000000000..254f4d0daa
--- /dev/null
+++ b/modules/stock/tests/scenario_stock_shipment_cron_assign.rst
@@ -0,0 +1,137 @@
+==========================
+Stock Shipment Cron Assign
+==========================
+
+Imports::
+
+    >>> import datetime as dt
+    >>> from decimal import Decimal
+
+    >>> from proteus import Model
+    >>> from trytond.modules.company.tests.tools import create_company, get_company
+    >>> from trytond.tests.tools import activate_modules
+
+    >>> today = dt.date.today()
+    >>> yesterday = today - dt.timedelta(days=1)
+
+Activate modules::
+
+    >>> config = activate_modules('stock')
+
+    >>> Cron = Model.get('ir.cron')
+    >>> Location = Model.get('stock.location')
+    >>> Move = Model.get('stock.move')
+    >>> Party = Model.get('party.party')
+    >>> ProductTemplate = Model.get('product.template')
+    >>> ShipmentInternal = Model.get('stock.shipment.internal')
+    >>> ShipmentOut = Model.get('stock.shipment.out')
+    >>> UoM = Model.get('product.uom')
+
+Create company::
+
+    >>> _ = create_company()
+    >>> company = get_company()
+
+Create a product::
+
+    >>> unit, = UoM.find([('name', '=', "Unit")])
+
+    >>> template = ProductTemplate()
+    >>> template.name = "Product"
+    >>> template.type = 'goods'
+    >>> template.default_uom = unit
+    >>> template.save()
+    >>> product, = template.products
+
+Create customer::
+
+    >>> customer = Party(name="Customer")
+    >>> customer.save()
+
+Get locations::
+
+    >>> storage_loc, = Location.find([('code', '=', "STO")])
+    >>> supplier_loc, = Location.find([('code', '=', "SUP")])
+    >>> lost_loc, = Location.find([('type', '=', 'lost_found')], limit=1)
+
+Fill storage::
+
+    >>> move = Move()
+    >>> move.product = product
+    >>> move.quantity = 5
+    >>> move.from_location = supplier_loc
+    >>> move.to_location = storage_loc
+    >>> move.unit_price = Decimal('10.0000')
+    >>> move.currency = company.currency
+    >>> move.effective_date = yesterday
+    >>> move.click('do')
+    >>> move.state
+    'done'
+
+Create different shipments with different planned dates::
+
+    >>> shipment_int_1 = ShipmentInternal()
+    >>> shipment_int_1.planned_date = today
+    >>> shipment_int_1.from_location = storage_loc
+    >>> shipment_int_1.to_location = lost_loc
+    >>> move = shipment_int_1.moves.new()
+    >>> move.from_location = shipment_int_1.from_location
+    >>> move.to_location = shipment_int_1.to_location
+    >>> move.product = product
+    >>> move.quantity = 2
+    >>> shipment_int_1.click('wait')
+    >>> shipment_int_1.state
+    'waiting'
+
+    >>> shipment_out_1 = ShipmentOut()
+    >>> shipment_out_1.planned_date = today
+    >>> shipment_out_1.customer = customer
+    >>> move = shipment_out_1.outgoing_moves.new()
+    >>> move.from_location = shipment_out_1.warehouse_output
+    >>> move.to_location = shipment_out_1.customer_location
+    >>> move.product = product
+    >>> move.quantity = 2
+    >>> move.unit_price = Decimal('10.0000')
+    >>> move.currency = company.currency
+    >>> shipment_out_1.click('wait')
+    >>> shipment_out_1.state
+    'waiting'
+
+    >>> shipment_int_2, = shipment_int_1.duplicate()
+    >>> shipment_int_2.click('wait')
+    >>> shipment_int_2.state
+    'waiting'
+
+    >>> shipment_out_2, = shipment_out_1.duplicate()
+    >>> shipment_out_2.click('wait')
+    >>> shipment_out_2.state
+    'waiting'
+
+Run assignation cron::
+
+    >>> cron = Cron(method='ir.cron|stock_shipment_assign_try')
+    >>> cron.interval_number = 1
+    >>> cron.interval_type = 'days'
+    >>> cron.click('run_once')
+
+Check assignations::
+
+    >>> shipment_int_1.reload()
+    >>> shipment_int_1.state
+    'assigned'
+
+    >>> shipment_out_1.reload()
+    >>> shipment_out_1.state
+    'assigned'
+
+    >>> shipment_int_2.reload()
+    >>> shipment_int_2.state
+    'waiting'
+    >>> shipment_int_2.partially_assigned
+    True
+
+    >>> shipment_out_2.reload()
+    >>> shipment_out_2.state
+    'waiting'
+    >>> shipment_out_2.partially_assigned
+    False