diff --git a/nummi/main/models.py b/nummi/main/models.py
index 3ddc8f8..53c4a25 100644
--- a/nummi/main/models.py
+++ b/nummi/main/models.py
@@ -3,7 +3,7 @@ import pathlib
 import uuid
 
 from django.conf import settings
-from django.core.validators import FileExtensionValidator
+from django.core.validators import FileExtensionValidator, validate_slug
 from django.db import models, transaction
 from django.urls import reverse
 from django.utils.translation import gettext as _
@@ -34,7 +34,10 @@ class Account(CustomModel):
     id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
     name = models.CharField(max_length=64, default=_("Account"), verbose_name=_("Name"))
     icon = models.CharField(
-        max_length=64, default="building-columns", verbose_name=_("Icon")
+        max_length=64,
+        default="building-columns",
+        verbose_name=_("Icon"),
+        validators=[validate_slug],
     )
 
     def __str__(self):
@@ -76,7 +79,12 @@ class Category(CustomModel):
     name = models.CharField(
         max_length=64, default=_("Category"), verbose_name=_("Name")
     )
-    icon = models.CharField(max_length=64, default="folder", verbose_name=_("Icon"))
+    icon = models.CharField(
+        max_length=64,
+        default="folder",
+        verbose_name=_("Icon"),
+        validators=[validate_slug],
+    )
     budget = models.BooleanField(default=True, verbose_name=_("Budget"))
 
     def __str__(self):