diff --git a/roles/tox/library/tox_install_sibling_packages.py b/roles/tox/library/tox_install_sibling_packages.py
index 915186c1b..75a82eda7 100644
--- a/roles/tox/library/tox_install_sibling_packages.py
+++ b/roles/tox/library/tox_install_sibling_packages.py
@@ -115,9 +115,15 @@ def get_installed_packages(tox_python):
     # Matches strings of the form:
     # 1. '<package_name>==<version>'
     # 2. '# Editable Git install with no remote (<package_name>==<version>)'
-    # both results: <package_name>
-    return [x[x.find('(') + 1:].split('==')[0]
-            for x in frozen_pkgs.split('\n') if '==' in x]
+    # 3. '<package_name> @ <URI_reference>' # PEP440, PEP508, PEP610
+    # results <package_name>
+    installed_packages = []
+    for x in frozen_pkgs.split('\n'):
+        if '==' in x:
+            installed_packages.append(x[x.find('(') + 1:].split('==')[0])
+        elif '@' in x:
+            installed_packages.append(x.split('@')[0].rstrip(' \t'))
+    return installed_packages
 
 
 def write_new_constraints_file(constraints, packages):