diff --git a/lib/wanda/catalog/check_customization.ex b/lib/wanda/catalog/check_customization.ex
new file mode 100644
index 00000000..66e412e3
--- /dev/null
+++ b/lib/wanda/catalog/check_customization.ex
@@ -0,0 +1,40 @@
+defmodule Wanda.Catalog.CheckCustomization do
+  @moduledoc """
+  Schema representing Customizations applied for a Check in a specific execution group.
+  """
+  use Ecto.Schema
+  import Ecto.Changeset
+
+  @fields ~w(id check_id group_id inserted_at updated_at)a
+  @required_fields ~w(check_id group_id)a
+
+  @custom_value_fields ~w(name value)a
+
+  @primary_key false
+  schema "check_customizations" do
+    field :id, Ecto.UUID, primary_key: true
+    field :check_id, :string
+    field :group_id, Ecto.UUID
+
+    embeds_many :custom_values, CustomValue, primary_key: false do
+      field :name, :string
+      field :value, :string
+    end
+
+    timestamps(type: :utc_datetime_usec)
+  end
+
+
+  def changeset(check_customization, attrs) do
+    check_customization
+    |> cast(attrs, @fields)
+    |> validate_required(@required_fields)
+    |> cast_embed(:custom_values, with: &custom_value_changeset/2, required: true)
+  end
+
+  defp custom_value_changeset(custom_value, attrs) do
+    custom_value
+    |> cast(attrs, @custom_value_fields)
+    |> validate_required(@custom_value_fields)
+  end
+end
diff --git a/priv/repo/migrations/20250123102550_create_check_customizations.exs b/priv/repo/migrations/20250123102550_create_check_customizations.exs
new file mode 100644
index 00000000..2ca19813
--- /dev/null
+++ b/priv/repo/migrations/20250123102550_create_check_customizations.exs
@@ -0,0 +1,18 @@
+defmodule Wanda.Repo.Migrations.CreateCheckCustomizations do
+  use Ecto.Migration
+
+  def change do
+    create table(:check_customizations, primary_key: false) do
+      add :id, :uuid, primary_key: true
+      add :check_id, :string, null: false
+      add :group_id, :uuid, null: false
+      add :custom_values, :jsonb, null: false, default: "[]"
+
+      timestamps()
+    end
+
+    create index(:check_customizations, [:check_id])
+    create index(:check_customizations, [:group_id])
+    create unique_index(:check_customizations, [:check_id, :group_id])
+  end
+end