diff --git a/azurerm/internal/services/storage/metadata.go b/azurerm/internal/services/storage/metadata.go
index a52fdc18e3d2..5358b1ce6600 100644
--- a/azurerm/internal/services/storage/metadata.go
+++ b/azurerm/internal/services/storage/metadata.go
@@ -1,11 +1,18 @@
 package storage
 
-import "github.com/hashicorp/terraform/helper/schema"
+import (
+	"fmt"
+	"regexp"
+	"strings"
+
+	"github.com/hashicorp/terraform/helper/schema"
+)
 
 func MetaDataSchema() *schema.Schema {
 	return &schema.Schema{
-		Type:     schema.TypeMap,
-		Optional: true,
+		Type:         schema.TypeMap,
+		Optional:     true,
+		ValidateFunc: validateMetaDataKeys,
 	}
 }
 
@@ -28,3 +35,105 @@ func FlattenMetaData(input map[string]string) map[string]interface{} {
 
 	return output
 }
+
+func validateMetaDataKeys(value interface{}, fieldName string) (warnings []string, errors []error) {
+	v, ok := value.(map[string]interface{})
+	if !ok {
+		return
+	}
+
+	for k := range v {
+		isCSharpKeyword := cSharpKeywords[strings.ToLower(k)] != nil
+		if isCSharpKeyword {
+			errors = append(errors, fmt.Errorf("%q is not a valid key (C# keyword)", k))
+		}
+
+		// must begin with a letter, underscore
+		// the rest: letters, digits and underscores
+		r, _ := regexp.Compile(`^([a-z_]{1}[a-z0-9_]{1,})$`)
+		if !r.MatchString(k) {
+			errors = append(errors, fmt.Errorf("MetaData must start with letters or an underscores. Got %q.", k))
+		}
+	}
+
+	return
+}
+
+var cSharpKeywords = map[string]*struct{}{
+	"abstract":   {},
+	"as":         {},
+	"base":       {},
+	"bool":       {},
+	"break":      {},
+	"byte":       {},
+	"case":       {},
+	"catch":      {},
+	"char":       {},
+	"checked":    {},
+	"class":      {},
+	"const":      {},
+	"continue":   {},
+	"decimal":    {},
+	"default":    {},
+	"delegate":   {},
+	"do":         {},
+	"double":     {},
+	"else":       {},
+	"enum":       {},
+	"event":      {},
+	"explicit":   {},
+	"extern":     {},
+	"false":      {},
+	"finally":    {},
+	"fixed":      {},
+	"float":      {},
+	"for":        {},
+	"foreach":    {},
+	"goto":       {},
+	"if":         {},
+	"implicit":   {},
+	"in":         {},
+	"int":        {},
+	"interface":  {},
+	"internal":   {},
+	"is":         {},
+	"lock":       {},
+	"long":       {},
+	"namespace":  {},
+	"new":        {},
+	"null":       {},
+	"object":     {},
+	"operator":   {},
+	"out":        {},
+	"override":   {},
+	"params":     {},
+	"private":    {},
+	"protected":  {},
+	"public":     {},
+	"readonly":   {},
+	"ref":        {},
+	"return":     {},
+	"sbyte":      {},
+	"sealed":     {},
+	"short":      {},
+	"sizeof":     {},
+	"stackalloc": {},
+	"static":     {},
+	"string":     {},
+	"struct":     {},
+	"switch":     {},
+	"this":       {},
+	"throw":      {},
+	"true":       {},
+	"try":        {},
+	"typeof":     {},
+	"uint":       {},
+	"ulong":      {},
+	"unchecked":  {},
+	"unsafe":     {},
+	"ushort":     {},
+	"using":      {},
+	"void":       {},
+	"volatile":   {},
+	"while":      {},
+}
diff --git a/azurerm/internal/services/storage/metadata_test.go b/azurerm/internal/services/storage/metadata_test.go
new file mode 100644
index 000000000000..84d045f49830
--- /dev/null
+++ b/azurerm/internal/services/storage/metadata_test.go
@@ -0,0 +1,61 @@
+package storage
+
+import "testing"
+
+func TestValidateMetaDataKeys(t *testing.T) {
+	testData := []struct {
+		Input    string
+		Expected bool
+	}{
+		{
+			Input:    "",
+			Expected: false,
+		},
+		{
+			Input:    "Hello",
+			Expected: false,
+		},
+		{
+			Input:    "hello",
+			Expected: true,
+		},
+		{
+			Input:    "hello",
+			Expected: true,
+		},
+		{
+			// C# keyword
+			Input:    "using",
+			Expected: false,
+		},
+		{
+			Input:    "0hello",
+			Expected: false,
+		},
+		{
+			Input:    "heLLo",
+			Expected: false,
+		},
+		{
+			Input:    "panda_cycle",
+			Expected: true,
+		},
+	}
+
+	for _, v := range testData {
+		t.Logf("[DEBUG] Testing %q", v.Input)
+
+		value := map[string]interface{}{
+			v.Input: "hello",
+		}
+		warnings, errors := validateMetaDataKeys(value, "field")
+		if len(warnings) != 0 {
+			t.Fatalf("Expected no warnings but got %d", len(warnings))
+		}
+
+		actual := len(errors) == 0
+		if v.Expected != actual {
+			t.Fatalf("Expected %t but got %t", v.Expected, actual)
+		}
+	}
+}
diff --git a/azurerm/resource_arm_storage_share_test.go b/azurerm/resource_arm_storage_share_test.go
index aee53fd106bf..dc96c7a1a952 100644
--- a/azurerm/resource_arm_storage_share_test.go
+++ b/azurerm/resource_arm_storage_share_test.go
@@ -319,7 +319,7 @@ resource "azurerm_storage_share" "test" {
   resource_group_name  = "${azurerm_resource_group.test.name}"
   storage_account_name = "${azurerm_storage_account.test.name}"
 
-  metadata {
+  metadata = {
     hello = "world"
   }
 }
@@ -336,7 +336,7 @@ resource "azurerm_storage_share" "test" {
   resource_group_name  = "${azurerm_resource_group.test.name}"
   storage_account_name = "${azurerm_storage_account.test.name}"
 
-  metadata {
+  metadata = {
     hello = "world"
     happy = "birthday"
   }