diff --git a/news/5273.bugfix.rst b/news/5273.bugfix.rst
new file mode 100644
index 0000000000..93e8fad698
--- /dev/null
+++ b/news/5273.bugfix.rst
@@ -0,0 +1 @@
+Fix issue where unnamed constraints were provided but which are not allowed by ``pip`` resolver.
diff --git a/pipenv/utils/dependencies.py b/pipenv/utils/dependencies.py
index a9990995d0..c23582660d 100644
--- a/pipenv/utils/dependencies.py
+++ b/pipenv/utils/dependencies.py
@@ -280,7 +280,7 @@ def is_constraints(dep: InstallRequirement) -> bool:
     constraints = []
     for dep_name, dep in deps.items():
         new_dep = Requirement.from_pipfile(dep_name, dep)
-        if is_constraints(new_dep.as_ireq()):
+        if new_dep.is_named and is_constraints(new_dep.as_ireq()):
             c = new_dep.as_line().strip()
             constraints.append(c)
     return constraints