diff --git a/src/cmd/go/internal/base/goflags.go b/src/cmd/go/internal/base/goflags.go
index 4da27550fd3..267006be7a2 100644
--- a/src/cmd/go/internal/base/goflags.go
+++ b/src/cmd/go/internal/base/goflags.go
@@ -92,7 +92,11 @@ func SetFromGOFLAGS(flags *flag.FlagSet) {
 	}
 	for _, goflag := range goflags {
 		name, value, hasValue := goflag, "", false
-		if i := strings.Index(goflag, "="); i >= 0 {
+		// Ignore invalid flags like '=' or '=value'.
+		// If it is not reported in InitGOFlags it means we don't want to report it.
+		if i := strings.Index(goflag, "="); i == 0 {
+			continue
+		} else if i > 0 {
 			name, value, hasValue = goflag[:i], goflag[i+1:], true
 		}
 		if strings.HasPrefix(name, "--") {
diff --git a/src/cmd/go/testdata/script/env_write.txt b/src/cmd/go/testdata/script/env_write.txt
index 24bb6f8f59d..0af22ed421c 100644
--- a/src/cmd/go/testdata/script/env_write.txt
+++ b/src/cmd/go/testdata/script/env_write.txt
@@ -24,6 +24,10 @@ stdout GOARCH=
 stdout GOOS=
 stdout GOROOT=
 
+# go env ignores invalid flag in GOFLAGS environment variable
+env GOFLAGS='=true'
+go env
+
 # checking errors
 ! go env -w
 stderr 'go env -w: no KEY=VALUE arguments given'