diff --git a/pkg/cmd/set/env/env_parse.go b/pkg/cmd/set/env/env_parse.go
index d5b3ec70..e93fed83 100644
--- a/pkg/cmd/set/env/env_parse.go
+++ b/pkg/cmd/set/env/env_parse.go
@@ -25,21 +25,16 @@ import (
 
 	"k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/util/sets"
+	"k8s.io/apimachinery/pkg/util/validation"
 )
 
 var argumentEnvironment = regexp.MustCompile("(?ms)^(.+)\\=(.*)$")
-var validArgumentEnvironment = regexp.MustCompile("(?ms)^(\\w+)\\=(.*)$")
 
 // IsEnvironmentArgument checks whether a string is an environment argument, that is, whether it matches the "anycharacters=anycharacters" pattern.
 func IsEnvironmentArgument(s string) bool {
 	return argumentEnvironment.MatchString(s)
 }
 
-// IsValidEnvironmentArgument checks whether a string is a valid environment argument, that is, whether it matches the "wordcharacters=anycharacters" pattern. Word characters can be letters, numbers, and underscores.
-func IsValidEnvironmentArgument(s string) bool {
-	return validArgumentEnvironment.MatchString(s)
-}
-
 // SplitEnvironmentFromResources separates resources from environment arguments.
 // Resources must come first. Arguments may have the "DASH-" syntax.
 func SplitEnvironmentFromResources(args []string) (resources, envArgs []string, ok bool) {
@@ -70,8 +65,6 @@ func parseIntoEnvVar(spec []string, defaultReader io.Reader, envVarType string)
 	var remove []string
 	for _, envSpec := range spec {
 		switch {
-		case !IsValidEnvironmentArgument(envSpec) && !strings.HasSuffix(envSpec, "-"):
-			return nil, nil, fmt.Errorf("%ss must be of the form key=value and can only contain letters, numbers, and underscores", envVarType)
 		case envSpec == "-":
 			if defaultReader == nil {
 				return nil, nil, fmt.Errorf("when '-' is used, STDIN must be open")
@@ -86,6 +79,9 @@ func parseIntoEnvVar(spec []string, defaultReader io.Reader, envVarType string)
 			if len(parts) != 2 {
 				return nil, nil, fmt.Errorf("invalid %s: %v", envVarType, envSpec)
 			}
+			if errs := validation.IsEnvVarName(parts[0]); len(errs) != 0 {
+				return nil, nil, fmt.Errorf("%q is not a valid key name: %s", parts[0], strings.Join(errs, ";"))
+			}
 			exists.Insert(parts[0])
 			env = append(env, v1.EnvVar{
 				Name:  parts[0],
diff --git a/pkg/cmd/set/env/env_parse_test.go b/pkg/cmd/set/env/env_parse_test.go
index 5cff84a1..e877e0c0 100644
--- a/pkg/cmd/set/env/env_parse_test.go
+++ b/pkg/cmd/set/env/env_parse_test.go
@@ -34,18 +34,6 @@ func ExampleIsEnvironmentArgument_false() {
 	// Output: false
 }
 
-func ExampleIsValidEnvironmentArgument_true() {
-	test := "wordcharacters=true"
-	fmt.Println(IsValidEnvironmentArgument(test))
-	// Output: true
-}
-
-func ExampleIsValidEnvironmentArgument_false() {
-	test := "not$word^characters=test"
-	fmt.Println(IsValidEnvironmentArgument(test))
-	// Output: false
-}
-
 func ExampleSplitEnvironmentFromResources() {
 	args := []string{`resource`, "ENV\\=ARG", `ONE\=MORE`, `DASH-`}
 	fmt.Println(SplitEnvironmentFromResources(args))
@@ -54,16 +42,40 @@ func ExampleSplitEnvironmentFromResources() {
 
 func ExampleParseEnv_good() {
 	r := strings.NewReader("FROM=READER")
-	ss := []string{"ENV=VARIABLE", "AND=ANOTHER", "REMOVE-", "-"}
+	ss := []string{"ENV=VARIABLE", "ENV.TEST=VARIABLE", "AND=ANOTHER", "REMOVE-", "-"}
 	fmt.Println(ParseEnv(ss, r))
 	// Output:
-	// [{ENV VARIABLE nil} {AND ANOTHER nil} {FROM READER nil}] [REMOVE] <nil>
+	// [{ENV VARIABLE nil} {ENV.TEST VARIABLE nil} {AND ANOTHER nil} {FROM READER nil}] [REMOVE] <nil>
 }
 
-func ExampleParseEnv_bad() {
+func ExampleParseEnv_bad_first() {
 	var r io.Reader
 	bad := []string{"This not in the key=value format."}
 	fmt.Println(ParseEnv(bad, r))
 	// Output:
-	// [] [] environment variables must be of the form key=value and can only contain letters, numbers, and underscores
+	// [] [] "This not in the key" is not a valid key name: a valid environment variable name must consist of alphabetic characters, digits, '_', '-', or '.', and must not start with a digit (e.g. 'my.env-name',  or 'MY_ENV.NAME',  or 'MyEnvName1', regex used for validation is '[-._a-zA-Z][-._a-zA-Z0-9]*')
+}
+
+func ExampleParseEnv_bad_second() {
+	var r io.Reader
+	bad := []string{".=VARIABLE"}
+	fmt.Println(ParseEnv(bad, r))
+	// Output:
+	// [] [] "." is not a valid key name: must not be '.'
+}
+
+func ExampleParseEnv_bad_third() {
+	var r io.Reader
+	bad := []string{"..=VARIABLE"}
+	fmt.Println(ParseEnv(bad, r))
+	// Output:
+	// [] [] ".." is not a valid key name: must not be '..'
+}
+
+func ExampleParseEnv_bad_fourth() {
+	var r io.Reader
+	bad := []string{"..ENV=VARIABLE"}
+	fmt.Println(ParseEnv(bad, r))
+	// Output:
+	// [] [] "..ENV" is not a valid key name: must not start with '..'
 }