Qatar has begun the process of giving citizenship back to nearly 5,000 people whose legal status had been disputed, a local human rights group said.
Khaled al-Attiya of the National Human Rights Committee said citizenship would be restored to those who had clarified their status and broke no laws.
Members of a tribe in southern Qatar had their nationality stripped because they also held Saudi citizenship.
Qatari law does not permit its 150,000 citizens to hold dual nationality.
The Gulf emirate's decision to deny nationality to members of the al-Murra tribe worsened its often tense relations with its giant neighbour.
Some Saudi reports suggested Qatar's decision had been retaliation for support given by the al-Murra tribe to the former emir, Sheikh Khalifa bin Hamad Al Thani, after he was deposed in 1995 by his son, Sheikh Hamad bin Khalifa.
The new emir survived an attempted coup in 1996.