The 13-month-old was found with serious injuries at her home in Barrow in December 2012.
A second inquest was ordered after a seven-minute hearing in 2014 determined Poppi's death was "unascertained".
It was due to be held in Kendal from 15 May and will be rescheduled for October while her father seeks legal aid.
Poppi Worthington death: Key dates
David Roberts, senior coroner for Cumbria, said the adjournment followed a request by Poppi's father, Paul Worthington, who had been unable to secure legal aid in sufficient time.
Mr Roberts said it was "of real importance for Mr Worthington to take part in the process and it will be difficult for him to do so in the absence of legal representation".
He added: "It is self-evident my findings and conclusion at the inquest may (depending upon what they are) have significant ramifications for Mr Worthington."
A family judge previously ruled the toddler had been sexually assaulted by her father, who has always denied any wrongdoing.
No-one has been charged in connection with Poppi's death. The Crown Prosecution Service (CPS) said it had no "realistic prospect" of securing a conviction.
The second inquest was initially suspended in September after the CPS carried out a review of the case, concluding it was right not to bring any charges against Mr Worthington.
The second inquest into the death of Cumbrian toddler Poppi Worthington has again been adjourned, a coroner has confirmed.