They were charged with corrupt practices linked to the Sharif family's ownership of luxury flats in London.
Hundreds of his supporters had gathered outside Adiala prison in the garrison city of Rawalpindi to await their release.
They were earlier sentenced to 10, seven and one year respectively in the case on July 6 by the Islamabad Accountability Court.
On Wednesday, Islamabad High Court judge Athar Minallah ruled that the National Accountability Bureau, Pakistan's anti-corruption watchdog, was unable to prove a financial link between the former prime minister and the apartments in question.
For Sharif, who was ousted from the premiership over graft allegations and ultimately landed in jail, the suspension of the sentence by the IHC is the kind of relief that has not only stirred up the country's political landscape but will also enable him to openly go back to public.
Following the judgment, Senator Chaudhary Tanvir submitted bail bonds for Nawaz, Maryam and Safdar at the deputy registrar's office of the high court.
The trio were briefly allowed out of the high-security Adiala Jail on parole to attend her funeral.
Nawaz's son-in-law Safdar was given 1-year imprisonment for not cooperating with the NAB, and aiding and abeting Nawaz and Maryam. His conviction would end only when the appeals challenging the July 6 judgment are also accepted.
A two member bench, led by Minallah, suspended the jail sentences while hearing the Sharifs' appeal against their convictions.
A large number of Pakistan Muslim League-Nawaz (PML-N) leaders, including Shehbaz Sharif, Pervaiz Rashid and Khurram Dastgir, were present in the courtroom for the hearing.
Earlier, when the case was taken up, NAB prosecutors continued presenting arguments on the suspension petitions.
The Avenfield case was among the three corruption cases filed against the three-time former premier and his children by the NAB on the Supreme Court's orders in the Panama Papers case which disqualified Sharif.