Judge Adeniyi Ademola, his wife Tolulope Olabowale and a senior lawyer, Joe Agi, were formally acquitted of 18 charges, including receiving money and gifts to influence cases.
Prosecutors claimed 30 million naira ($98,000, 92,000 euros) was found in his wife’s bank account and his son was given a BMW car as a gift.
Investigators were also to have found foreign currency and two unlicensed guns at his house.But Judge Jude Okeke, sitting at the Federal High Court in Abuja, agreed with a defence submission made in February that their clients had no case to answer.
He described the charges as “highly speculative” and lacking merit.
Ademola has been involved in a number of high-profile cases, including the trial of a Boko Haram Islamist fighter who masterminded a Christmas Day 2011 church bombing that killed 44.
In 2015, he ordered the release on bail of pro-Biafra leader Nnamdi Kanu and ex-national chief Sambo Dasuki, who is accused of diverting money meant to buy arms to fight Boko Haram.
Buhari, who was elected on a pledge to root out high-level corruption, has said both should not be released, despite not being convicted.
Ademola was one of seven judges arrested on suspicion of corruption in October last year in an unprecedented nationwide sting. One was a member of the Supreme Court.
The main opposition Peoples Democratic Party (PDP) has accused Buhari of conducting a political witch-hunt, given that most of those arrested are from the previous administration.