diff --git a/README.md b/README.md
index 67433ea..edf6025 100644
--- a/README.md
+++ b/README.md
@@ -541,7 +541,7 @@ External providers from plugins should define the provider module at
 
   Each symbol table should have these fields:
   - name: string -- displayed in the outline
-  - kind: integer -- determines the icon to use
+  - kind: integer|string -- determines the icon to use
   - selectionRange: table with fields `start` and `end`, each have fields
   `line` and `character`, each integers:
   `{ start = { line = ?, character = ? }, ['end'] = { line = ?, character = ? } }`
diff --git a/lua/outline/parser.lua b/lua/outline/parser.lua
index 3f3415d..fc31d76 100644
--- a/lua/outline/parser.lua
+++ b/lua/outline/parser.lua
@@ -6,6 +6,15 @@ local utils = require('outline.utils.init')
 
 local M = {}
 
+local function norm_kind(kind)
+  if type(kind) == 'number' then
+    return kind
+  else
+    -- string
+    return symbols.str_to_kind[kind] or 21 -- fallback to Null
+  end
+end
+
 ---Parses result from LSP into a reorganized tree of symbols (not flattened,
 -- simply reoganized by merging each property table from the arguments into a
 -- table for each symbol)
@@ -20,6 +29,7 @@ local function parse_result(result, depth, hierarchy, parent, bufnr)
 
   for index, value in pairs(result) do
     -- FIXME: If a parent was excluded, all children will not be considered
+    value.kind = norm_kind(value.kind)
     if cfg.should_include_symbol(symbols.kinds[value.kind], bufnr) then
       -- the hierarchy is basically a table of booleans which
       -- tells whether the parent was the last in its group or