Ahmad Tibi (Arabic: أحمد الطيبي [ˈ(ʔ)æħmæd (atˤ)ˈtˤiːbi]; Hebrew: אַחְמָד טִיבִּי [ˈ(ʔ)aχmed ˈtibi], sometimes spelled Ahmed Tibi; born 19 December 1958) is a Palestinian-Israeli politician. The leader of the Ta'al party, he has served as a member of the Knesset since 1999. Tibi was acknowledged as a figure in the Israeli-Palestinian arena after serving as a political advisor to the late Palestinian president Yasser Arafat (1993–1999).

Tibi is also a trained physician and graduate of the Hebrew University of Jerusalem as a gynecologist.

Tibi was born in Tayibe, a town about 16 kilometres east of the Mediterranean coast north of Tel Aviv, in 1958. His father, Kamal Tibi, was born in Jaffa.

Tibi studied medicine at the Hebrew University of Jerusalem, graduating with honors in 1983. He began a residency as a gynecologist at Hadassah Hospital in 1984, but in 1987, he was involved in a violent incident with a security guard that led to his dismissal. Tibi had walked past a security checkpoint when the guard, a recent American immigrant named David Rothstein who had just been hired, ordered Tibi to let him inspect his briefcase after he had walked past the guard booth, assuming the guard would recognize him. Tibi refused, which led to a physical struggle between him and Rothstein for the briefcase. Moments later, Rothstein's superior arrived and broke it up. He identified Tibi as a doctor, and ordered him released. Tibi then swung the briefcase at Rothstein's head, causing a wound that bled profusely and required four stitches to close, and walked away, leaving Rothstein bleeding on the floor. Tibi claimed that Rothstein had tried to slap him across the mouth as they disengaged, which Rothstein denied. The hospital director, Jacques Michel, subsequently questioned Tibi, Rothstein, and a few witnesses over the incident, then fired Tibi without conducting a formal inquiry. A hospital spokeswoman said that Michel felt that to strike a man and leave him injured on the floor was such a grave and violent act for a doctor to commit as to warrant dismissal.

During his studies, Tibi had also become involved in politics. In the 1980s, he made connections with prominent Palestinian activists. He attended PLO meetings around the world, and in 1984, he met Yasser Arafat in Tunis, at a time when meeting PLO members was still a criminal offense in Israel. Tibi was questioned by police several times, subjected to a stay of exit order from Israel, and arrested once.

Tibi served as a political advisor to Palestinian Authority President Yasser Arafat from 1993 to 1999, representing the Palestinians at the 1998 Wye River negotiations. He resigned from this post in 1999 upon deciding to run for the Knesset. Tibi described his relationship with Arafat as "close" and "extremely interesting and important to [him]".

He was first elected to the Knesset in the 1999 elections after establishing Ta'al and running jointly with Azmi Bishara's Balad party, but broke away during the same Knesset session.

In 2002, MK Michael Kleiner initiated actions in the Knesset to restrict movements by Tibi inside the Gaza Strip and the West Bank. Kleiner claimed that Tibi was assisting the Palestinians in their war against Israel. Tibi protested the Knesset's decision as unconstitutional and illegal under Israeli law, and appealed to the Supreme Court of Israel, which deferred a decision on the case.