diff --git a/cmd/root.go b/cmd/root.go
index 0c71f2db..8e629f29 100644
--- a/cmd/root.go
+++ b/cmd/root.go
@@ -3,6 +3,7 @@ package cmd
 import (
 	"os"
 	"strconv"
+	"strings"
 
 	"github.com/mgutz/ansi"
 	"github.com/spf13/cobra"
@@ -54,6 +55,13 @@ func New() *cobra.Command {
 				}
 			}
 
+			if !cmd.Flags().Changed("output") {
+				v, set := os.LookupEnv("HELM_DIFF_OUTPUT")
+				if set && strings.TrimSpace(v) != "" {
+					_ = cmd.Flags().Set("output", v)
+				}
+			}
+
 			nc, _ := cmd.Flags().GetBool("no-color")
 
 			if nc || (fc != nil && !*fc) {