diff --git a/internal/cli/unlockers.go b/internal/cli/unlockers.go
index 87b3d7e..2e1e3de 100644
--- a/internal/cli/unlockers.go
+++ b/internal/cli/unlockers.go
@@ -314,7 +314,8 @@ func (cli *Instance) UnlockersList(jsonOutput bool) error {
 		return err
 	}
 
-	var unlockers []UnlockerInfo
+	// Not nil, so that a vault with no unlockers prints [] in JSON, not null
+	unlockers := make([]UnlockerInfo, 0, len(unlockerMetadata))
 
 	for _, unlockerID := range slices.Sorted(maps.Keys(unlockerMetadata)) {
 		metadata := unlockerMetadata[unlockerID]
diff --git a/internal/cli/unlockers_list_test.go b/internal/cli/unlockers_list_test.go
index 0d72990..0d082d6 100644
--- a/internal/cli/unlockers_list_test.go
+++ b/internal/cli/unlockers_list_test.go
@@ -8,6 +8,8 @@
 //   - TestUnlockersListSkipsUnreadableMetadata: an unlocker whose metadata
 //     file cannot be checked for or read is left out, and the other is
 //     still listed.
+//   - TestUnlockersListEmptyJSON: a vault with no unlockers lists them as
+//     an empty JSON list.
 
 //nolint:testpackage // white-box test of unexported internals
 package cli
@@ -321,3 +323,36 @@ func TestUnlockersListSkipsUnreadableMetadata(t *testing.T) {
 		})
 	}
 }
+
+// TestUnlockersListEmptyJSON is a regression test for
+// https://git.eeqj.de/sneak/secret/issues/148: listing the unlockers of a
+// vault that has none, as after its last unlocker is removed, printed
+// "unlockers": null in JSON form instead of an empty list.
+func TestUnlockersListEmptyJSON(t *testing.T) {
+	t.Parallel()
+
+	fs := afero.NewMemMapFs()
+	vaultDir := filepath.Join(listTestStateDir, "vaults.d", listTestVaultName)
+
+	require.NoError(t, afero.WriteFile(
+		fs, filepath.Join(listTestStateDir, "currentvault"),
+		[]byte(listTestVaultName), listTestFilePerm,
+	))
+	require.NoError(t, fs.MkdirAll(
+		filepath.Join(vaultDir, listTestUnlockersDirName), listTestDirPerm,
+	))
+
+	var buf bytes.Buffer
+
+	cmd := &cobra.Command{}
+	cmd.SetOut(&buf)
+
+	instance := &Instance{fs: fs, stateDir: listTestStateDir, cmd: cmd}
+	require.NoError(t, instance.UnlockersList(true))
+
+	var decoded map[string]any
+
+	require.NoError(t, json.Unmarshal(buf.Bytes(), &decoded))
+	assert.Equal(t, []any{}, decoded["unlockers"],
+		"no unlockers must be printed as [], not %s", buf.String())
+}
diff --git a/internal/cli/vault_list_test.go b/internal/cli/vault_list_test.go
new file mode 100644
index 0000000..8a216dd
--- /dev/null
+++ b/internal/cli/vault_list_test.go
@@ -0,0 +1,42 @@
+package cli_test
+
+import (
+	"bytes"
+	"encoding/json"
+	"path/filepath"
+	"testing"
+
+	"github.com/spf13/afero"
+	"github.com/spf13/cobra"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"sneak.berlin/go/secret/internal/cli"
+	"sneak.berlin/go/secret/internal/secret"
+)
+
+// TestVaultListEmptyJSON is a regression test for
+// https://git.eeqj.de/sneak/secret/issues/148: listing the vaults when
+// vaults.d holds none printed "vaults": null in JSON form instead of an
+// empty list.
+func TestVaultListEmptyJSON(t *testing.T) {
+	t.Parallel()
+
+	fs := afero.NewMemMapFs()
+	require.NoError(t, fs.MkdirAll(
+		filepath.Join(testStateDir, "vaults.d"), secret.DirPerms,
+	))
+
+	var buf bytes.Buffer
+
+	cmd := &cobra.Command{}
+	cmd.SetOut(&buf)
+
+	c := cli.NewCLIInstanceWithStateDir(fs, testStateDir)
+	require.NoError(t, c.ListVaults(cmd, true))
+
+	var decoded map[string]any
+
+	require.NoError(t, json.Unmarshal(buf.Bytes(), &decoded))
+	assert.Equal(t, []any{}, decoded["vaults"],
+		"no vaults must be printed as [], not %s", buf.String())
+}
diff --git a/internal/vault/management.go b/internal/vault/management.go
index 5bf9f3f..26d894f 100644
--- a/internal/vault/management.go
+++ b/internal/vault/management.go
@@ -140,8 +140,9 @@ func ListVaults(fs afero.Fs, stateDir string) ([]string, error) {
 		return nil, fmt.Errorf("failed to read vaults directory: %w", err)
 	}
 
-	// Extract vault names
-	var vaults []string
+	// Extract vault names. Not nil, so that no vaults prints [] in JSON,
+	// not null.
+	vaults := make([]string, 0, len(entries))
 
 	for _, entry := range entries {
 		if entry.IsDir() {