diff --git a/lumi2/ldap.py b/lumi2/ldap.py
index d2f182b..e3d3b81 100644
--- a/lumi2/ldap.py
+++ b/lumi2/ldap.py
@@ -16,7 +16,7 @@ from flask import current_app
 from ldap3 import Connection, Server, ALL, Reader, Writer, ObjectDef
 from PIL import Image
 
-from lumi2.usermodel import User
+from lumi2.usermodel import User, Group
 from lumi2.exceptions import MissingConfigKeyError
 
 
diff --git a/lumi2/usermodel.py b/lumi2/usermodel.py
index 9a6a20f..9b6d16f 100644
--- a/lumi2/usermodel.py
+++ b/lumi2/usermodel.py
@@ -250,8 +250,103 @@ class User:
         self.picture = picture
 
 
+    def __eq__(self, other):
+        return self.username == other.username
+
+    def __ne__(self, other):
+        return self.username != other.username
+
+    def __lt__(self, other):
+        return self.username < other.username
+
+    def __hash__(self):
+        return hash(self.username)
+
     def __repr__(self):
         repr_str = f'User("{self.username}", "{self.password_hash}", ' \
                    f'"{self.email}", "{self.first_name}", "{self.last_name}", ' \
                    f'"{self.display_name}", "{self.picture}")'
         return repr_str
+
+
+class Group:
+    """Class model for a group of users.
+
+    Attributes
+    ----------
+    groupname : str
+        The name (cn) of this group.
+    members : set[User]
+        The set of Users who are a member of this group.
+    """
+
+    @staticmethod
+    def is_valid_groupname(input_str: str) -> bool:
+        """Checks whether the input string is a valid group name.
+
+        A valid group name consists of only alphanumeric characters, starts with
+        a latin character and has minimum length 1.
+
+        Parameters
+        ----------
+        input_str : str
+            The string to check for validity as a group name.
+
+        Returns
+        -------
+        bool
+            True if input_str is a valid group name, and False otherwise.
+
+        Raises
+        ------
+        TypeError
+            If input_str is not of type string.
+        """
+
+        if not isinstance(input_str, str):
+            raise TypeError(f"Expected a string but got: '{type(input_str)}'.")
+
+        if not len(input_str):
+            return False
+
+        if input_str[0] not in ascii_lowercase + ascii_uppercase:
+            return False
+
+        for char in input_str:
+            if not char in ascii_uppercase + ascii_lowercase + digits:
+                return False
+
+        return True
+
+
+    def __init__(self, groupname: str, members: set[User]):
+
+        if not Group.is_valid_groupname(groupname):
+            raise ValueError("Not a valid group name: '{groupname}'.")
+        self.groupname = groupname
+
+        if not isinstance(members, set):
+            raise TypeError(f"Expected a set but got: '{type(members)}'.")
+        for member in members:
+            if not isinstance(member, User):
+                raise TypeError(f"Expected only Users in members set but got: '{type(member)}'.")
+        if not len(members):
+            raise ValueError("Expected at least one group member.")
+        self.members = members
+
+
+    def __eq__(self, other):
+        return self.groupname == other.groupname
+
+    def __ne__(self, other):
+        return self.groupname != other.groupname
+
+    def __lt__(self, other):
+        return self.groupname < other.groupname
+
+    def __hash__(self):
+        return hash(self.groupname)
+
+    def __repr__(self):
+        repr_str = f'Group("{self.groupname}", "{self.members}")'
+        return repr_str