Zarah Garde-Wilson (born c. 1978) is an Australian criminal defence lawyer and principal partner at Garde Wilson Lawyers. She is known for her role in the Melbourne gangland wars and the subsequent Lawyer X scandal. Throughout her career, she has represented a number of high-profile figures, including Carl Williams, Tony Mokbel, and Fadi Haddara.

Garde-Wilson's legal career became linked with Melbourne's underworld following the murder of her then boyfriend, convicted killer Lewis Caine, in 2004. She was convicted of contempt of court in 2005, after she refused to testify in Caine's murder trial. Her experiences during the Melbourne gangland wars led to her involvement in matters concerning barrister Nicola Gobbo's role as a police informant, known as Lawyer X scandal, and later gave testimony at the subsequent Royal Commission into the Management of Police Informants, which scrutinized the conduct of Victoria Police.

Following the Lawyer X scandal, Garde-Wilson has represented clients who appealed against their convictions in matters linked to the scandal, as well as continuing her criticism of corruption within the Australian criminal justice system and her advocacy for defendants' rights. She has also been involved in defamation proceedings against Google and far-right activist Avi Yemini. Her role in Melbourne's gangland wars was dramatised in the television series Underbelly and Fat Tony & Co.

Garde-Wilson received her secondary education at Fairholme College, in Toowoomba, Queensland. She later moved to Perth, Western Australia, to study law at the University of Western Australia.

Upon finishing university, Garde-Wilson worked as a law clerk for the law firm Pryles & Defteros. After working for Pryles & Defteros, she went into independent practice as principle at Garde Wilson Lawyers. In 2024, Garde-Wilson was listed among "The 8 best criminal lawyers in Melbourne" by The Canberra Times.

Garde-Wilson came into the public eye during the Melbourne gangland killings as a legal representative for several persons investigated by the Victoria Police from 1998 to 2006 in relation to the killings, specifically the high-profile trials of Carl Williams and Tony Mokbel. Garde-Wilson was the girlfriend of convicted murderer Lewis Caine, who was murdered in the gangland killings. In 2005, Garde-Wilson was found guilty of contempt of court after refusing to testify against the two men charged with the murder of her boyfriend Lewis Caine, saying that she feared for her life.

In the course of he involvement, she represented several high-profile clients who were unknowingly compromised by their own attorney, Nicola Gobbo, who was secretly acting as a police informant under the codename "Informer 3838" (also known as Lawyer X). Garde-Wilson's concerns about leaks within the legal system and her public questioning of the legal integrity of Victoria Police began to intensify during the late 2000s. However, her calls for broader public and legal scrutiny that eventually exposed Nicola Gobbo's role as "Informer 3838" escalated significantly around 2018 when the media first publicly disclosed Gobbo's role as an informant.

Following the revelations surrounding Nicola Gobbo's dual role as a lawyer and a police informant, the Royal Commission into the Management of Police Informants was established. Garde-Wilson provided testimony during this inquiry, which scrutinized the conduct of Victoria Police and the implications of using a legal professional as an informant. In response to the Commission's findings and the subsequent impact on public trust in the justice system, Garde-Wilson, along with other prominent Australian lawyers, called for significant reforms. In July 2023, following the closure of the Lawyer X Office of the Special Investigator, these legal practitioners, including Garde-Wilson, demanded an official apology from former Victorian Premier Daniel Andrews, emphasizing the need for reforms to restore integrity within the judicial system.