diff --git a/docs/docs/changelog.md b/docs/docs/changelog.md
index 63c9bff1..d9700449 100644
--- a/docs/docs/changelog.md
+++ b/docs/docs/changelog.md
@@ -14,6 +14,7 @@ title: Changelog
 * `[Added]` Support `env_file` in global config and commands. File names are expanded after `env` is resolved, and values loaded from env files override values from `env`.
 * `[Changed]` Migrate the LSP YAML parser from the CGO-based tree-sitter bindings to pure-Go [`gotreesitter`](https://github.com/odvcencio/gotreesitter), removing the C toolchain requirement from normal builds and release packaging.
 * `[Refactoring]` Move CLI startup flow from `cmd/lets/main.go` into `internal/cli/cli.go`, keeping `main.go` as a thin launcher.
+* `[Added]` Add `lets self doc` command to open the online documentation in a browser.
 
 ## [0.0.59](https://github.com/lets-cli/lets/releases/tag/v0.0.59)
 
diff --git a/internal/cli/cli.go b/internal/cli/cli.go
index eb0b1107..d84d2a23 100644
--- a/internal/cli/cli.go
+++ b/internal/cli/cli.go
@@ -161,10 +161,29 @@ func getExitCode(err error, defaultCode int) int {
 	return defaultCode
 }
 
-// do not fail on config error in it is help (-h, --help) or --init or completion command.
+// do not fail on config error if it is help (-h, --help), --init, completion, or lets self.
 func failOnConfigError(root *cobra.Command, current *cobra.Command, rootFlags *flags) bool {
-	rootCommands := set.NewSet("completion", "help", "lsp")
-	return (root.Flags().NFlag() == 0 && !rootCommands.Contains(current.Name())) && !rootFlags.help && !rootFlags.init
+	return (root.Flags().NFlag() == 0 && !allowsMissingConfig(current)) && !rootFlags.help && !rootFlags.init
+}
+
+func allowsMissingConfig(current *cobra.Command) bool {
+	if current == nil {
+		return false
+	}
+
+	switch current.Name() {
+	case "completion", "help":
+		return true
+	}
+
+	for cmd := current; cmd != nil; cmd = cmd.Parent() {
+		parent := cmd.Parent()
+		if cmd.Name() == "self" && parent != nil && parent.Name() == "lets" {
+			return true
+		}
+	}
+
+	return false
 }
 
 type flags struct {
diff --git a/internal/cli/cli_test.go b/internal/cli/cli_test.go
new file mode 100644
index 00000000..9915e9ff
--- /dev/null
+++ b/internal/cli/cli_test.go
@@ -0,0 +1,59 @@
+package cli
+
+import (
+	"testing"
+
+	cmdpkg "github.com/lets-cli/lets/internal/cmd"
+	"github.com/spf13/cobra"
+)
+
+func TestAllowsMissingConfig(t *testing.T) {
+	t.Run("help", func(t *testing.T) {
+		command := &cobra.Command{Use: "help"}
+		if !allowsMissingConfig(command) {
+			t.Fatal("expected help to allow missing config")
+		}
+	})
+
+	t.Run("completion", func(t *testing.T) {
+		root := cmdpkg.CreateRootCommand("v0.0.0-test", "")
+		cmdpkg.InitCompletionCmd(root, nil)
+
+		command, _, err := root.Find([]string{"completion"})
+		if err != nil {
+			t.Fatalf("unexpected error: %v", err)
+		}
+
+		if !allowsMissingConfig(command) {
+			t.Fatal("expected completion to allow missing config")
+		}
+	})
+
+	t.Run("self subcommand", func(t *testing.T) {
+		root := cmdpkg.CreateRootCommand("v0.0.0-test", "")
+		cmdpkg.InitSelfCmd(root, "v0.0.0-test")
+
+		command, _, err := root.Find([]string{"self", "doc"})
+		if err != nil {
+			t.Fatalf("unexpected error: %v", err)
+		}
+
+		if !allowsMissingConfig(command) {
+			t.Fatal("expected lets self doc to allow missing config")
+		}
+	})
+
+	t.Run("top level doc does not match self", func(t *testing.T) {
+		root := cmdpkg.CreateRootCommand("v0.0.0-test", "")
+		root.AddCommand(&cobra.Command{Use: "doc"})
+
+		command, _, err := root.Find([]string{"doc"})
+		if err != nil {
+			t.Fatalf("unexpected error: %v", err)
+		}
+
+		if allowsMissingConfig(command) {
+			t.Fatal("expected top-level doc to require config")
+		}
+	})
+}
diff --git a/internal/cmd/doc.go b/internal/cmd/doc.go
new file mode 100644
index 00000000..b88d7807
--- /dev/null
+++ b/internal/cmd/doc.go
@@ -0,0 +1,29 @@
+package cmd
+
+import (
+	"fmt"
+
+	"github.com/spf13/cobra"
+)
+
+const letsDocsURL = "https://lets-cli.org/docs/config"
+
+func initDocCommand(openURL func(string) error) *cobra.Command {
+	docCmd := &cobra.Command{
+		Use:     "doc",
+		Aliases: []string{"docs"},
+		Short:   "Open lets documentation in browser",
+		Args:    cobra.NoArgs,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			if err := openURL(letsDocsURL); err != nil {
+				return fmt.Errorf("can not open documentation: %w", err)
+			}
+
+			fmt.Fprintf(cmd.OutOrStdout(), "Opening %s\n", letsDocsURL)
+
+			return nil
+		},
+	}
+
+	return docCmd
+}
diff --git a/internal/cmd/root_test.go b/internal/cmd/root_test.go
index 1c311bf7..1cd5ddfe 100644
--- a/internal/cmd/root_test.go
+++ b/internal/cmd/root_test.go
@@ -176,6 +176,61 @@ func TestPrintVersionMessage(t *testing.T) {
 }
 
 func TestSelfCmd(t *testing.T) {
+	t.Run("should open documentation in browser", func(t *testing.T) {
+		bufOut := new(bytes.Buffer)
+		called := false
+		gotURL := ""
+
+		openURL := func(url string) error {
+			called = true
+			gotURL = url
+
+			return nil
+		}
+
+		rootCmd := CreateRootCommand("v0.0.0-test", "")
+		rootCmd.SetArgs([]string{"self", "doc"})
+		rootCmd.SetOut(bufOut)
+		rootCmd.SetErr(bufOut)
+		initSelfCmd(rootCmd, "v0.0.0-test", openURL)
+
+		err := rootCmd.Execute()
+		if err != nil {
+			t.Fatalf("unexpected error: %v", err)
+		}
+
+		if !called {
+			t.Fatal("expected documentation opener to be called")
+		}
+
+		if gotURL != letsDocsURL {
+			t.Fatalf("expected docs url %q, got %q", letsDocsURL, gotURL)
+		}
+	})
+
+	t.Run("should return opener error for documentation command", func(t *testing.T) {
+		bufOut := new(bytes.Buffer)
+
+		openURL := func(url string) error {
+			return errors.New("open failed")
+		}
+
+		rootCmd := CreateRootCommand("v0.0.0-test", "")
+		rootCmd.SetArgs([]string{"self", "doc"})
+		rootCmd.SetOut(bufOut)
+		rootCmd.SetErr(bufOut)
+		initSelfCmd(rootCmd, "v0.0.0-test", openURL)
+
+		err := rootCmd.Execute()
+		if err == nil {
+			t.Fatal("expected documentation opener error")
+		}
+
+		if !strings.Contains(err.Error(), "can not open documentation") {
+			t.Fatalf("expected documentation error, got %q", err.Error())
+		}
+	})
+
 	t.Run("should return exit code 2 for unknown self subcommand", func(t *testing.T) {
 		bufOut := new(bytes.Buffer)
 
diff --git a/internal/cmd/self.go b/internal/cmd/self.go
index fe1cf4d8..1d80b956 100644
--- a/internal/cmd/self.go
+++ b/internal/cmd/self.go
@@ -1,11 +1,16 @@
 package cmd
 
 import (
+	"github.com/lets-cli/lets/internal/util"
 	"github.com/spf13/cobra"
 )
 
 // InitSelfCmd intializes root 'self' subcommand.
 func InitSelfCmd(rootCmd *cobra.Command, version string) {
+	initSelfCmd(rootCmd, version, util.OpenURL)
+}
+
+func initSelfCmd(rootCmd *cobra.Command, version string, openURL func(string) error) {
 	selfCmd := &cobra.Command{
 		Use:     "self",
 		Hidden:  false,
@@ -19,5 +24,6 @@ func InitSelfCmd(rootCmd *cobra.Command, version string) {
 
 	rootCmd.AddCommand(selfCmd)
 
+	selfCmd.AddCommand(initDocCommand(openURL))
 	selfCmd.AddCommand(initLspCommand(version))
 }
diff --git a/internal/util/browser.go b/internal/util/browser.go
new file mode 100644
index 00000000..de0e07ea
--- /dev/null
+++ b/internal/util/browser.go
@@ -0,0 +1,35 @@
+package util
+
+import (
+	"fmt"
+	"os/exec"
+	"runtime"
+)
+
+func browserCommand(goos string, url string) (*exec.Cmd, error) {
+	switch goos {
+	case "darwin":
+		return exec.Command("open", url), nil
+	case "linux":
+		return exec.Command("xdg-open", url), nil
+	default:
+		return nil, fmt.Errorf("unsupported platform %q", goos)
+	}
+}
+
+func OpenURL(url string) error {
+	cmd, err := browserCommand(runtime.GOOS, url)
+	if err != nil {
+		return err
+	}
+
+	if err := cmd.Start(); err != nil {
+		return fmt.Errorf("start %s: %w", cmd.Path, err)
+	}
+
+	if cmd.Process != nil {
+		_ = cmd.Process.Release()
+	}
+
+	return nil
+}
diff --git a/internal/util/browser_test.go b/internal/util/browser_test.go
new file mode 100644
index 00000000..449e9d5a
--- /dev/null
+++ b/internal/util/browser_test.go
@@ -0,0 +1,51 @@
+package util
+
+import (
+	"reflect"
+	"strings"
+	"testing"
+)
+
+func TestBrowserCommand(t *testing.T) {
+	t.Run("darwin", func(t *testing.T) {
+		cmd, err := browserCommand("darwin", "https://lets-cli.org")
+		if err != nil {
+			t.Fatalf("unexpected error: %v", err)
+		}
+
+		if cmd.Args[0] != "open" {
+			t.Fatalf("expected open, got %q", cmd.Args[0])
+		}
+
+		expectedArgs := []string{"open", "https://lets-cli.org"}
+		if !reflect.DeepEqual(cmd.Args, expectedArgs) {
+			t.Fatalf("expected args %v, got %v", expectedArgs, cmd.Args)
+		}
+	})
+
+	t.Run("linux", func(t *testing.T) {
+		cmd, err := browserCommand("linux", "https://lets-cli.org")
+		if err != nil {
+			t.Fatalf("unexpected error: %v", err)
+		}
+
+		if cmd.Args[0] != "xdg-open" {
+			t.Fatalf("expected xdg-open, got %q", cmd.Args[0])
+		}
+
+		expectedArgs := []string{"xdg-open", "https://lets-cli.org"}
+		if !reflect.DeepEqual(cmd.Args, expectedArgs) {
+			t.Fatalf("expected args %v, got %v", expectedArgs, cmd.Args)
+		}
+	})
+
+	t.Run("unsupported", func(t *testing.T) {
+		_, err := browserCommand("windows", "https://lets-cli.org")
+		if err == nil {
+			t.Fatal("expected unsupported platform error")
+		}
+		if !strings.Contains(err.Error(), "windows") {
+			t.Fatalf("expected error to mention platform %q, got %q", "windows", err.Error())
+		}
+	})
+}
diff --git a/tests/no_lets_file.bats b/tests/no_lets_file.bats
index 59f1bd26..d2e9293e 100644
--- a/tests/no_lets_file.bats
+++ b/tests/no_lets_file.bats
@@ -8,6 +8,22 @@ setup() {
 }
 
 NOT_EXISTED_LETS_FILE="lets-not-existed.yaml"
+TEMP_FAKE_BIN_DIR=""
+TEMP_OPENED_URL_FILE=""
+
+teardown() {
+    if [[ -n "${TEMP_FAKE_BIN_DIR}" ]]; then
+        rm -rf "${TEMP_FAKE_BIN_DIR}"
+    fi
+
+    if [[ -n "${TEMP_OPENED_URL_FILE}" ]]; then
+        rm -f "${TEMP_OPENED_URL_FILE}"
+    fi
+
+    TEMP_FAKE_BIN_DIR=""
+    TEMP_OPENED_URL_FILE=""
+    cleanup
+}
 
 @test "no_lets_file: should not create .lets dir" {
     LETS_CONFIG=${NOT_EXISTED_LETS_FILE} run lets
@@ -49,4 +65,40 @@ NOT_EXISTED_LETS_FILE="lets-not-existed.yaml"
     LETS_CONFIG=${NOT_EXISTED_LETS_FILE} run lets -h
     assert_success
     assert_line --index 0  "A CLI task runner"
-}
\ No newline at end of file
+}
+
+@test "no_lets_file: lets self doc opens docs without config" {
+    TEMP_FAKE_BIN_DIR="$(mktemp -d)"
+    TEMP_OPENED_URL_FILE="$(mktemp)"
+    rm -f "${TEMP_OPENED_URL_FILE}"
+
+    cat > "${TEMP_FAKE_BIN_DIR}/xdg-open" <<'EOF'
+#!/usr/bin/env bash
+printf "%s" "$1" > "${LETS_TEST_OPENED_URL_FILE}"
+EOF
+    chmod +x "${TEMP_FAKE_BIN_DIR}/xdg-open"
+
+    cat > "${TEMP_FAKE_BIN_DIR}/open" <<'EOF'
+#!/usr/bin/env bash
+printf "%s" "$1" > "${LETS_TEST_OPENED_URL_FILE}"
+EOF
+    chmod +x "${TEMP_FAKE_BIN_DIR}/open"
+
+    PATH="${TEMP_FAKE_BIN_DIR}:${PATH}" \
+    LETS_CONFIG=${NOT_EXISTED_LETS_FILE} \
+    LETS_TEST_OPENED_URL_FILE="${TEMP_OPENED_URL_FILE}" \
+    run lets self doc
+
+    assert_success
+
+    for _ in $(seq 1 20); do
+        if [[ -f "${TEMP_OPENED_URL_FILE}" ]]; then
+            break
+        fi
+        sleep 0.1
+    done
+
+    run cat "${TEMP_OPENED_URL_FILE}"
+    assert_success
+    assert_output "https://lets-cli.org/docs/config"
+}