diff --git a/pipenv/project.py b/pipenv/project.py
index b96487c1..cb34f689 100644
--- a/pipenv/project.py
+++ b/pipenv/project.py
@@ -1226,6 +1226,7 @@ class Project:
             newly_added = True
 
         p[category][normalized_name] = entry
+        p[category] = dict(sorted(p[category].items()))
 
         # Write Pipfile.
         self.write_toml(p)
diff --git a/tests/integration/test_install_basic.py b/tests/integration/test_install_basic.py
index 02d5b855..bf4d2f13 100644
--- a/tests/integration/test_install_basic.py
+++ b/tests/integration/test_install_basic.py
@@ -556,3 +556,20 @@ dataclasses-json = {file = "https://files.pythonhosted.org/packages/85/94/1b3021
         assert c.returncode == 0
         c = p.pipenv("""run python -c "from dataclasses_json import dataclass_json" """)
         assert c.returncode == 0
+
+@pytest.mark.basic
+@pytest.mark.install
+def test_packages_sorted_alphabetically_in_category(pipenv_instance_private_pypi):
+    with pipenv_instance_private_pypi() as p:
+        with open(p.pipfile_path, "w") as f:
+            contents = """
+[packages]
+atomicwrites = "*"
+colorama = "*"
+            """.strip()
+            f.write(contents)
+        c = p.pipenv("install build")
+        assert c.returncode == 0
+        assert "build" in p.pipfile["packages"]
+        assert list(p.pipfile["packages"].keys()) == ["atomicwrites", "build", "colorama"]
+