diff --git a/cmd/orphan.go b/cmd/orphan.go
index 7b5f9eb..97ab54b 100644
--- a/cmd/orphan.go
+++ b/cmd/orphan.go
@@ -4,6 +4,7 @@ package cmd
 import (
 	"fmt"
 	"os"
+	"slices"
 
 	"github.com/boneskull/gh-stack/internal/config"
 	"github.com/boneskull/gh-stack/internal/git"
@@ -59,7 +60,30 @@ func runOrphan(cmd *cobra.Command, args []string) error {
 
 	node := tree.FindNode(root, branchName)
 	if node == nil {
-		return fmt.Errorf("branch %q is not tracked", branchName)
+		// FindNode walks Parent->Children links starting from trunk, so a
+		// branch whose recorded parent is missing or itself untracked is
+		// disconnected from the tree even though it still has a
+		// stackParent entry in git config. Treat that as orphan-able
+		// rather than rejecting: the branch IS tracked, the link is just
+		// dangling. (#116)
+		trackedBranches, listErr := cfg.ListTrackedBranches()
+		if listErr != nil {
+			return fmt.Errorf("branch %q is not tracked", branchName)
+		}
+		if !slices.Contains(trackedBranches, branchName) {
+			return fmt.Errorf("branch %q is not tracked", branchName)
+		}
+		// A disconnected branch has no children in the in-memory tree
+		// (children require a parent link from this branch, which Build
+		// would have wired up before disconnecting it), so drop straight
+		// into the cleanup path without the children check.
+		s := style.New()
+		_ = cfg.RemoveParent(branchName)    //nolint:errcheck // best effort cleanup
+		_ = cfg.RemovePR(branchName)        //nolint:errcheck // best effort cleanup
+		_ = cfg.RemoveForkPoint(branchName) //nolint:errcheck // best effort cleanup
+		_ = cfg.RemovePRBase(branchName)    //nolint:errcheck // best effort cleanup
+		fmt.Printf("%s Orphaned %s\n", s.SuccessIcon(), s.Branch(branchName))
+		return nil
 	}
 
 	// Check for children
diff --git a/e2e/orphan_test.go b/e2e/orphan_test.go
index 50793fc..46d7ac6 100644
--- a/e2e/orphan_test.go
+++ b/e2e/orphan_test.go
@@ -53,3 +53,29 @@ func TestOrphanForceClearsPRBaseOnDescendants(t *testing.T) {
 		t.Errorf("expected feat-b stackPRBase cleared, got %q", v)
 	}
 }
+
+func TestOrphanDisconnectedBranchIsAllowed(t *testing.T) {
+	env := NewTestEnv(t)
+	env.MustRun("init")
+
+	// Create the branch chain main -> feat-a, then manually delete the
+	// parent link so feat-a's recorded parent ("missing-branch") is not
+	// itself a tracked branch. This mirrors the scenario in #116 where
+	// the parent is no longer valid and `gh stack orphan` previously
+	// refused to orphan the current branch.
+	env.MustRun("create", "feat-a")
+	env.CreateCommit("feat-a work")
+	env.Git("config", "branch.feat-a.stackParent", "missing-branch")
+
+	if env.GetStackConfig("branch.feat-a.stackParent") != "missing-branch" {
+		t.Fatal("expected feat-a parent override to land before orphan")
+	}
+
+	result := env.Run("orphan", "feat-a")
+	if !result.Success() {
+		t.Fatalf("expected orphan of disconnected branch to succeed, got exit %d stderr=%q", result.ExitCode, result.Stderr)
+	}
+	if v := env.GetStackConfig("branch.feat-a.stackParent"); v != "" {
+		t.Errorf("expected feat-a stackParent cleared after orphan, got %q", v)
+	}
+}