diff --git a/app_test.go b/app_test.go
index 46ec33f..b224d63 100644
--- a/app_test.go
+++ b/app_test.go
@@ -627,6 +627,23 @@ func TestAppCommandNotFound(t *testing.T) {
 	expect(t, subcommandRun, false)
 }
 
+func TestGlobalFlag(t *testing.T) {
+	var globalFlag string
+	var globalFlagSet bool
+	app := cli.NewApp()
+	app.Flags = []cli.Flag{
+		cli.StringFlag{Name: "global, g", Usage: "global"},
+	}
+	app.Action = func(c *cli.Context) {
+		globalFlag = c.GlobalString("global")
+		globalFlagSet = c.GlobalIsSet("global")
+	}
+	app.Run([]string{"command", "-g", "foo"})
+	expect(t, globalFlag, "foo")
+	expect(t, globalFlagSet, true)
+
+}
+
 func TestGlobalFlagsInSubcommands(t *testing.T) {
 	subcommandRun := false
 	parentFlag := false
diff --git a/context.go b/context.go
index c75607e..f541f41 100644
--- a/context.go
+++ b/context.go
@@ -73,7 +73,7 @@ func (c *Context) Generic(name string) interface{} {
 
 // Looks up the value of a global int flag, returns 0 if no int flag exists
 func (c *Context) GlobalInt(name string) int {
-	if fs := lookupParentFlagSet(name, c); fs != nil {
+	if fs := lookupGlobalFlagSet(name, c); fs != nil {
 		return lookupInt(name, fs)
 	}
 	return 0
@@ -81,7 +81,7 @@ func (c *Context) GlobalInt(name string) int {
 
 // Looks up the value of a global time.Duration flag, returns 0 if no time.Duration flag exists
 func (c *Context) GlobalDuration(name string) time.Duration {
-	if fs := lookupParentFlagSet(name, c); fs != nil {
+	if fs := lookupGlobalFlagSet(name, c); fs != nil {
 		return lookupDuration(name, fs)
 	}
 	return 0
@@ -89,7 +89,7 @@ func (c *Context) GlobalDuration(name string) time.Duration {
 
 // Looks up the value of a global bool flag, returns false if no bool flag exists
 func (c *Context) GlobalBool(name string) bool {
-	if fs := lookupParentFlagSet(name, c); fs != nil {
+	if fs := lookupGlobalFlagSet(name, c); fs != nil {
 		return lookupBool(name, fs)
 	}
 	return false
@@ -97,7 +97,7 @@ func (c *Context) GlobalBool(name string) bool {
 
 // Looks up the value of a global string flag, returns "" if no string flag exists
 func (c *Context) GlobalString(name string) string {
-	if fs := lookupParentFlagSet(name, c); fs != nil {
+	if fs := lookupGlobalFlagSet(name, c); fs != nil {
 		return lookupString(name, fs)
 	}
 	return ""
@@ -105,7 +105,7 @@ func (c *Context) GlobalString(name string) string {
 
 // Looks up the value of a global string slice flag, returns nil if no string slice flag exists
 func (c *Context) GlobalStringSlice(name string) []string {
-	if fs := lookupParentFlagSet(name, c); fs != nil {
+	if fs := lookupGlobalFlagSet(name, c); fs != nil {
 		return lookupStringSlice(name, fs)
 	}
 	return nil
@@ -113,7 +113,7 @@ func (c *Context) GlobalStringSlice(name string) []string {
 
 // Looks up the value of a global int slice flag, returns nil if no int slice flag exists
 func (c *Context) GlobalIntSlice(name string) []int {
-	if fs := lookupParentFlagSet(name, c); fs != nil {
+	if fs := lookupGlobalFlagSet(name, c); fs != nil {
 		return lookupIntSlice(name, fs)
 	}
 	return nil
@@ -121,7 +121,7 @@ func (c *Context) GlobalIntSlice(name string) []int {
 
 // Looks up the value of a global generic flag, returns nil if no generic flag exists
 func (c *Context) GlobalGeneric(name string) interface{} {
-	if fs := lookupParentFlagSet(name, c); fs != nil {
+	if fs := lookupGlobalFlagSet(name, c); fs != nil {
 		return lookupGeneric(name, fs)
 	}
 	return nil
@@ -147,7 +147,11 @@ func (c *Context) IsSet(name string) bool {
 func (c *Context) GlobalIsSet(name string) bool {
 	if c.globalSetFlags == nil {
 		c.globalSetFlags = make(map[string]bool)
-		for ctx := c.parentContext; ctx != nil && c.globalSetFlags[name] == false; ctx = ctx.parentContext {
+		ctx := c
+		if ctx.parentContext != nil {
+			ctx = ctx.parentContext
+		}
+		for ; ctx != nil && c.globalSetFlags[name] == false; ctx = ctx.parentContext {
 			ctx.flagSet.Visit(func(f *flag.Flag) {
 				c.globalSetFlags[f.Name] = true
 			})
@@ -229,8 +233,11 @@ func (a Args) Swap(from, to int) error {
 	return nil
 }
 
-func lookupParentFlagSet(name string, ctx *Context) *flag.FlagSet {
-	for ctx := ctx.parentContext; ctx != nil; ctx = ctx.parentContext {
+func lookupGlobalFlagSet(name string, ctx *Context) *flag.FlagSet {
+	if ctx.parentContext != nil {
+		ctx = ctx.parentContext
+	}
+	for ; ctx != nil; ctx = ctx.parentContext {
 		if f := ctx.flagSet.Lookup(name); f != nil {
 			return ctx.flagSet
 		}