diff --git a/keysparsing.go b/keysparsing.go
index 6bdb0b8..528f1de 100644
--- a/keysparsing.go
+++ b/keysparsing.go
@@ -5,6 +5,7 @@
 import (
 	"bytes"
 	"fmt"
+	"unicode"
 )
 
 func parseKey(key string) ([]string, error) {
@@ -51,5 +52,5 @@
 }
 
 func isValidBareChar(r rune) bool {
-	return isAlphanumeric(r) || r == '-'
+	return isAlphanumeric(r) || r == '-' || unicode.IsNumber(r)
 }
diff --git a/lexer.go b/lexer.go
index e6c3566..f162565 100644
--- a/lexer.go
+++ b/lexer.go
@@ -253,9 +253,14 @@
 
 func (l *tomlLexer) lexKey() tomlLexStateFn {
 	l.ignore()
+	inQuotes := false
 	for r := l.next(); isKeyChar(r); r = l.next() {
-		if r == '#' {
-			return l.errorf("keys cannot contain # character")
+		if r == '"' {
+			inQuotes = !inQuotes
+		} else if isSpace(r) && !inQuotes {
+			break
+		} else if !isValidBareChar(r) && !inQuotes {
+			return l.errorf("keys cannot contain %c character", r)
 		}
 	}
 	l.backup()
diff --git a/lexer_test.go b/lexer_test.go
index 683d7f7..6b18a57 100644
--- a/lexer_test.go
+++ b/lexer_test.go
@@ -124,10 +124,7 @@
 
 func TestKeyWithSymbolsAndEqual(t *testing.T) {
 	testFlow(t, "~!@$^&*()_+-`1234567890[]\\|/?><.,;:' = 5", []token{
-		token{Position{1, 1}, tokenKey, "~!@$^&*()_+-`1234567890[]\\|/?><.,;:'"},
-		token{Position{1, 38}, tokenEqual, "="},
-		token{Position{1, 40}, tokenInteger, "5"},
-		token{Position{1, 41}, tokenEOF, ""},
+		token{Position{1, 1}, tokenError, "keys cannot contain ~ character"},
 	})
 }
 
@@ -549,3 +546,12 @@
 		token{Position{1, 8}, tokenEOF, ""},
 	})
 }
+
+func TestQuotedKey(t *testing.T) {
+	testFlow(t, "\"a b\" = 42", []token{
+		token{Position{1, 1}, tokenKey, "\"a b\""},
+		token{Position{1, 7}, tokenEqual, "="},
+		token{Position{1, 9}, tokenInteger, "42"},
+		token{Position{1, 11}, tokenEOF, ""},
+	})
+}
diff --git a/parser.go b/parser.go
index e4d1083..8911261 100644
--- a/parser.go
+++ b/parser.go
@@ -192,13 +192,21 @@
 	}
 
 	// assign value to the found group
-	localKey := []string{key.val}
-	finalKey := append(groupKey, key.val)
+	keyVals, err := parseKey(key.val)
+	if err != nil {
+		p.raiseError(key, "%s", err)
+	}
+	if len(keyVals) != 1 {
+		p.raiseError(key, "Invalid key")
+	}
+	keyVal := keyVals[0]
+	localKey := []string{keyVal}
+	finalKey := append(groupKey, keyVal)
 	if targetNode.GetPath(localKey) != nil {
 		p.raiseError(key, "The following key was defined twice: %s",
 			strings.Join(finalKey, "."))
 	}
-	targetNode.values[key.val] = &tomlValue{value, key.Position}
+	targetNode.values[keyVal] = &tomlValue{value, key.Position}
 	return p.parseStart
 }
 
diff --git a/parser_test.go b/parser_test.go
index d33ddde..7a88055 100644
--- a/parser_test.go
+++ b/parser_test.go
@@ -51,12 +51,10 @@
 	})
 }
 
-// NOTE: from the BurntSushi test suite
-// NOTE: this test is pure evil due to the embedded '.'
-func TestSpecialKV(t *testing.T) {
-	tree, err := Load("~!@$^&*()_+-`1234567890[]\\|/?><.,;: = 1")
+func TestNumberInKey(t *testing.T) {
+	tree, err := Load("hello2 = 42")
 	assertTree(t, tree, err, map[string]interface{}{
-		"~!@$^&*()_+-`1234567890[]\\|/?><.,;:": int64(1),
+		"hello2": int64(42),
 	})
 }
 
@@ -109,6 +107,13 @@
 	})
 }
 
+func TestSpaceKey(t *testing.T) {
+	tree, err := Load("\"a b\" = \"hello world\"")
+	assertTree(t, tree, err, map[string]interface{}{
+		"a b": "hello world",
+	})
+}
+
 func TestStringEscapables(t *testing.T) {
 	tree, err := Load("a = \"a \\n b\"")
 	assertTree(t, tree, err, map[string]interface{}{
diff --git a/token.go b/token.go
index 6c0bcc6..f0fbac9 100644
--- a/token.go
+++ b/token.go
@@ -120,7 +120,7 @@
 	// Keys start with the first character that isn't whitespace or [ and end
 	// with the last non-whitespace character before the equals sign. Keys
 	// cannot contain a # character."
-	return !(isSpace(r) || r == '\r' || r == '\n' || r == eof || r == '=')
+	return !(r == '\r' || r == '\n' || r == eof || r == '=')
 }
 
 func isKeyStartChar(r rune) bool {