diff --git a/global.go b/global.go
index de1b4d8..6ccab96 100644
--- a/global.go
+++ b/global.go
@@ -3,6 +3,7 @@ package main
 import (
 	"context"
 	"io"
+	"os"
 	"time"
 
 	"github.com/hymkor/gmnlisp"
@@ -138,3 +139,15 @@ func (g *Global) expectX(ctx context.Context, w *gmnlisp.World, node gmnlisp.Nod
 		return gmnlisp.Progn(ctx, w, timeoutAct)
 	}
 }
+
+func (g *Global) getenv(ctx context.Context, w *gmnlisp.World, arg gmnlisp.Node) (gmnlisp.Node, error) {
+	name, err := gmnlisp.ExpectClass[gmnlisp.String](ctx, w, arg)
+	if err != nil {
+		return nil, err
+	}
+	value, ok := os.LookupEnv(string(name))
+	if !ok {
+		return gmnlisp.Null, nil
+	}
+	return gmnlisp.String(value), nil
+}
diff --git a/main.go b/main.go
index d406fa5..94cd66c 100644
--- a/main.go
+++ b/main.go
@@ -33,6 +33,7 @@ func mains(args []string) error {
 			gmnlisp.NewSymbol("spawn"):   &gmnlisp.Function{Min: 1, F: g.spawn},
 			gmnlisp.NewSymbol("expect*"): gmnlisp.SpecialF(g.expectX),
 			gmnlisp.NewSymbol("expect"):  gmnlisp.SpecialF(g.expect),
+			gmnlisp.NewSymbol("getenv"):  gmnlisp.Function1(g.getenv),
 		})
 
 	if len(args) <= 0 {