diff --git a/internal/github/actions.go b/internal/github/actions.go
index b464e63..a22e7da 100644
--- a/internal/github/actions.go
+++ b/internal/github/actions.go
@@ -34,6 +34,9 @@ type ActionRef struct {
 //   - "actions/checkout@v5" -> {Owner: "actions", Repo: "checkout", Version: "v5"}
 //   - "actions/setup-node@v4" -> {Owner: "actions", Repo: "setup-node", Version: "v4"}
 func ParseActionRef(ref string) (*ActionRef, error) {
+	// Trim whitespace (including newlines, spaces, tabs)
+	ref = strings.TrimSpace(ref)
+
 	if ref == "" {
 		return nil, fmt.Errorf("action reference cannot be empty")
 	}
diff --git a/internal/github/actions_test.go b/internal/github/actions_test.go
new file mode 100644
index 0000000..b40cc64
--- /dev/null
+++ b/internal/github/actions_test.go
@@ -0,0 +1,110 @@
+package github
+
+import (
+	"testing"
+)
+
+func TestParseActionRef(t *testing.T) {
+	tests := []struct {
+		name        string
+		input       string
+		wantOwner   string
+		wantRepo    string
+		wantVersion string
+		wantErr     bool
+	}{
+		{
+			name:        "valid action reference",
+			input:       "actions/checkout@v5",
+			wantOwner:   "actions",
+			wantRepo:    "checkout",
+			wantVersion: "v5",
+			wantErr:     false,
+		},
+		{
+			name:        "valid action with trailing newline",
+			input:       "actions/checkout@v5\n",
+			wantOwner:   "actions",
+			wantRepo:    "checkout",
+			wantVersion: "v5",
+			wantErr:     false,
+		},
+		{
+			name:        "valid action with leading and trailing whitespace",
+			input:       "  actions/checkout@v5  ",
+			wantOwner:   "actions",
+			wantRepo:    "checkout",
+			wantVersion: "v5",
+			wantErr:     false,
+		},
+		{
+			name:        "valid action with tabs and newlines",
+			input:       "\t\nactions/checkout@v5\n\t",
+			wantOwner:   "actions",
+			wantRepo:    "checkout",
+			wantVersion: "v5",
+			wantErr:     false,
+		},
+		{
+			name:        "complex action reference with whitespace",
+			input:       "kula-app/wait-for-services-action@v1\n",
+			wantOwner:   "kula-app",
+			wantRepo:    "wait-for-services-action",
+			wantVersion: "v1",
+			wantErr:     false,
+		},
+		{
+			name:    "empty string",
+			input:   "",
+			wantErr: true,
+		},
+		{
+			name:    "only whitespace",
+			input:   "   \n\t  ",
+			wantErr: true,
+		},
+		{
+			name:    "missing version",
+			input:   "actions/checkout",
+			wantErr: true,
+		},
+		{
+			name:    "missing repo",
+			input:   "actions@v5",
+			wantErr: true,
+		},
+		{
+			name:    "invalid format - too many slashes",
+			input:   "actions/github/checkout@v5",
+			wantErr: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := ParseActionRef(tt.input)
+
+			if tt.wantErr {
+				if err == nil {
+					t.Errorf("ParseActionRef() expected error but got none")
+				}
+				return
+			}
+
+			if err != nil {
+				t.Errorf("ParseActionRef() unexpected error: %v", err)
+				return
+			}
+
+			if got.Owner != tt.wantOwner {
+				t.Errorf("ParseActionRef() Owner = %v, want %v", got.Owner, tt.wantOwner)
+			}
+			if got.Repo != tt.wantRepo {
+				t.Errorf("ParseActionRef() Repo = %v, want %v", got.Repo, tt.wantRepo)
+			}
+			if got.Version != tt.wantVersion {
+				t.Errorf("ParseActionRef() Version = %v, want %v", got.Version, tt.wantVersion)
+			}
+		})
+	}
+}