diff --git a/CHANGELOG.md b/CHANGELOG.md
index 679f07ef..8498408a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Changelog
 
+## Unreleased
+
+- Add support for yaml extension ([#584](https://github.com/go-task/task/issues/584))
+
 ## v3.9.2 - 2021-12-02
 
 - Upgrade [mvdan/sh](https://github.com/mvdan/sh) which contains a fix a for
diff --git a/cmd/task/task.go b/cmd/task/task.go
index 2f7a11c0..ae2d4f90 100644
--- a/cmd/task/task.go
+++ b/cmd/task/task.go
@@ -77,7 +77,7 @@ func main() {
 
 	pflag.BoolVar(&versionFlag, "version", false, "show Task version")
 	pflag.BoolVarP(&helpFlag, "help", "h", false, "shows Task usage")
-	pflag.BoolVarP(&init, "init", "i", false, "creates a new Taskfile.yml in the current folder")
+	pflag.BoolVarP(&init, "init", "i", false, "creates a new Taskfile.yaml in the current folder")
 	pflag.BoolVarP(&list, "list", "l", false, "lists tasks with description of current Taskfile")
 	pflag.BoolVar(&status, "status", false, "exits with non-zero exit code if any of the given tasks is not up-to-date")
 	pflag.BoolVarP(&force, "force", "f", false, "forces execution even when the task is up-to-date")
@@ -122,8 +122,6 @@ func main() {
 	if entrypoint != "" {
 		dir = filepath.Dir(entrypoint)
 		entrypoint = filepath.Base(entrypoint)
-	} else {
-		entrypoint = "Taskfile.yml"
 	}
 
 	e := task.Executor{
diff --git a/completion/zsh/_task b/completion/zsh/_task
index 48777e4b..2bd4ac40 100755
--- a/completion/zsh/_task
+++ b/completion/zsh/_task
@@ -4,7 +4,7 @@
 function __list() {
     local -a scripts
 
-    if [ -f Taskfile.yml ]; then
+    if [ -f Taskfile.yml ] || [ -f Taskfile.yaml ]; then
         scripts=($(task -l | sed '1d' | sed 's/^\* //' | awk '{ print $1 }' | sed 's/:$//' | sed 's/:/\\:/g'))
         _describe 'script' scripts
     fi
diff --git a/init.go b/init.go
index 1c1d043f..2bddb210 100644
--- a/init.go
+++ b/init.go
@@ -23,7 +23,7 @@ tasks:
 
 // InitTaskfile Taskfile creates a new Taskfile
 func InitTaskfile(w io.Writer, dir string) error {
-	f := filepath.Join(dir, "Taskfile.yml")
+	f := filepath.Join(dir, "Taskfile.yaml")
 
 	if _, err := os.Stat(f); err == nil {
 		return ErrTaskfileAlreadyExists
@@ -32,6 +32,6 @@ func InitTaskfile(w io.Writer, dir string) error {
 	if err := os.WriteFile(f, []byte(defaultTaskfile), 0644); err != nil {
 		return err
 	}
-	fmt.Fprintf(w, "Taskfile.yml created in the current directory\n")
+	fmt.Fprintf(w, "Taskfile.yaml created in the current directory\n")
 	return nil
 }
diff --git a/task.go b/task.go
index c1c4e286..7021b77a 100644
--- a/task.go
+++ b/task.go
@@ -105,10 +105,6 @@ func (e *Executor) Run(ctx context.Context, calls ...taskfile.Call) error {
 
 // Setup setups Executor's internal state
 func (e *Executor) Setup() error {
-	if e.Entrypoint == "" {
-		e.Entrypoint = "Taskfile.yml"
-	}
-
 	var err error
 	e.Taskfile, err = read.Taskfile(e.Dir, e.Entrypoint)
 	if err != nil {
diff --git a/task_test.go b/task_test.go
index db83a851..f8e396f7 100644
--- a/task_test.go
+++ b/task_test.go
@@ -24,10 +24,11 @@ func init() {
 // fileContentTest provides a basic reusable test-case for running a Taskfile
 // and inspect generated files.
 type fileContentTest struct {
-	Dir       string
-	Target    string
-	TrimSpace bool
-	Files     map[string]string
+	Dir        string
+	Entrypoint string
+	Target     string
+	TrimSpace  bool
+	Files      map[string]string
 }
 
 func (fct fileContentTest) name(file string) string {
@@ -40,9 +41,10 @@ func (fct fileContentTest) Run(t *testing.T) {
 	}
 
 	e := &task.Executor{
-		Dir:    fct.Dir,
-		Stdout: io.Discard,
-		Stderr: io.Discard,
+		Dir:        fct.Dir,
+		Entrypoint: fct.Entrypoint,
+		Stdout:     io.Discard,
+		Stderr:     io.Discard,
 	}
 	assert.NoError(t, e.Setup(), "e.Setup()")
 	assert.NoError(t, e.Run(context.Background(), taskfile.Call{Task: fct.Target}), "e.Run(target)")
@@ -550,11 +552,11 @@ func TestStatusVariables(t *testing.T) {
 
 func TestInit(t *testing.T) {
 	const dir = "testdata/init"
-	var file = filepath.Join(dir, "Taskfile.yml")
+	var file = filepath.Join(dir, "Taskfile.yaml")
 
 	_ = os.Remove(file)
 	if _, err := os.Stat(file); err == nil {
-		t.Errorf("Taskfile.yml should not exist")
+		t.Errorf("Taskfile.yaml should not exist")
 	}
 
 	if err := task.InitTaskfile(io.Discard, dir); err != nil {
@@ -562,8 +564,9 @@ func TestInit(t *testing.T) {
 	}
 
 	if _, err := os.Stat(file); err != nil {
-		t.Errorf("Taskfile.yml should exist")
+		t.Errorf("Taskfile.yaml should exist")
 	}
+	_ = os.Remove(file)
 }
 
 func TestCyclicDep(t *testing.T) {
@@ -790,6 +793,21 @@ func TestIncludesOptionalExplicitFalse(t *testing.T) {
 	assert.Equal(t, "stat testdata/includes_optional_explicit_false/TaskfileOptional.yml: no such file or directory", err.Error())
 }
 
+func TestIncludesFromCustomTaskfile(t *testing.T) {
+	tt := fileContentTest{
+		Dir:        "testdata/includes_yaml",
+		Entrypoint: "Custom.ext",
+		Target:     "default",
+		TrimSpace:  true,
+		Files: map[string]string{
+			"main.txt":                         "main",
+			"included_with_yaml_extension.txt": "included_with_yaml_extension",
+			"included_with_custom_file.txt":    "included_with_custom_file",
+		},
+	}
+	tt.Run(t)
+}
+
 func TestSummary(t *testing.T) {
 	const dir = "testdata/summary"
 
diff --git a/taskfile/read/taskfile.go b/taskfile/read/taskfile.go
index 5ca194a3..ec7a3ab9 100644
--- a/taskfile/read/taskfile.go
+++ b/taskfile/read/taskfile.go
@@ -19,14 +19,26 @@ var (
 	ErrIncludedTaskfilesCantHaveIncludes = errors.New("task: Included Taskfiles can't have includes. Please, move the include to the main Taskfile")
 	// ErrIncludedTaskfilesCantHaveDotenvs is returned when a included Taskfile contains dotenvs
 	ErrIncludedTaskfilesCantHaveDotenvs = errors.New("task: Included Taskfiles can't have dotenv declarations. Please, move the dotenv declaration to the main Taskfile")
+
+	defaultTaskfiles = []string{"Taskfile.yml", "Taskfile.yaml"}
 )
 
 // Taskfile reads a Taskfile for a given directory
+// Uses current dir when dir is left empty. Uses Taskfile.yml
+// or Taskfile.yaml when entrypoint is left empty
 func Taskfile(dir string, entrypoint string) (*taskfile.Taskfile, error) {
-	path := filepath.Join(dir, entrypoint)
-	if _, err := os.Stat(path); err != nil {
-		return nil, fmt.Errorf(`task: No Taskfile found on "%s". Use "task --init" to create a new one`, path)
+	if dir == "" {
+		d, err := os.Getwd()
+		if err != nil {
+			return nil, err
+		}
+		dir = d
 	}
+	path, err := exists(filepath.Join(dir, entrypoint))
+	if err != nil {
+		return nil, err
+	}
+
 	t, err := readTaskfile(path)
 	if err != nil {
 		return nil, err
@@ -59,16 +71,14 @@ func Taskfile(dir string, entrypoint string) (*taskfile.Taskfile, error) {
 			path = filepath.Join(dir, path)
 		}
 
-		info, err := os.Stat(path)
+		path, err = exists(path)
 		if err != nil {
 			if includedTask.Optional {
 				return nil
 			}
 			return err
 		}
-		if info.IsDir() {
-			path = filepath.Join(path, "Taskfile.yml")
-		}
+
 		includedTaskfile, err := readTaskfile(path)
 		if err != nil {
 			return err
@@ -141,3 +151,22 @@ func readTaskfile(file string) (*taskfile.Taskfile, error) {
 	var t taskfile.Taskfile
 	return &t, yaml.NewDecoder(f).Decode(&t)
 }
+
+func exists(path string) (string, error) {
+	fi, err := os.Stat(path)
+	if err != nil {
+		return "", err
+	}
+	if fi.Mode().IsRegular() {
+		return path, nil
+	}
+
+	for _, n := range defaultTaskfiles {
+		fpath := filepath.Join(path, n)
+		if _, err := os.Stat(fpath); err == nil {
+			return fpath, nil
+		}
+	}
+
+	return "", fmt.Errorf(`task: No Taskfile found in "%s". Use "task --init" to create a new one`, path)
+}
diff --git a/testdata/includes_yaml/.gitignore b/testdata/includes_yaml/.gitignore
new file mode 100644
index 00000000..2211df63
--- /dev/null
+++ b/testdata/includes_yaml/.gitignore
@@ -0,0 +1 @@
+*.txt
diff --git a/testdata/includes_yaml/Custom.ext b/testdata/includes_yaml/Custom.ext
new file mode 100644
index 00000000..5264ca1e
--- /dev/null
+++ b/testdata/includes_yaml/Custom.ext
@@ -0,0 +1,16 @@
+version: '3'
+
+includes:
+  included: ./included
+  custom: ./included/custom.yaml
+
+tasks:
+  default:
+    cmds:
+      - task: gen
+      - task: included:gen
+      - task: custom:gen
+
+  gen:
+    cmds:
+      - echo main > main.txt
diff --git a/testdata/includes_yaml/included/Taskfile.yaml b/testdata/includes_yaml/included/Taskfile.yaml
new file mode 100644
index 00000000..6e3f4962
--- /dev/null
+++ b/testdata/includes_yaml/included/Taskfile.yaml
@@ -0,0 +1,6 @@
+version: '3'
+
+tasks:
+  gen:
+    cmds:
+      - echo included_with_yaml_extension > included_with_yaml_extension.txt
diff --git a/testdata/includes_yaml/included/custom.yaml b/testdata/includes_yaml/included/custom.yaml
new file mode 100644
index 00000000..f72e199f
--- /dev/null
+++ b/testdata/includes_yaml/included/custom.yaml
@@ -0,0 +1,6 @@
+version: '3'
+
+tasks:
+  gen:
+    cmds:
+      - echo included_with_custom_file > included_with_custom_file.txt