It will if you recursively define it: from collections import defaultdict def dd(): return defaultdict(dd) d = dd() d['a']['b']['c'] # => defa

It will if you recursively define it: from collections import defaultdict def dd(): return defaultdict(dd) d = dd() d['a']['b']['c'] # => defaultdict(dd, {}) d['a']['b']['c'] = 'test' d['a']['b']['c'] # => 'test'