"It is an outstanding record. I hope such a success will promise more effective activity of competent women in all fields," Rouhani tweeted, according to IRNA.
Thirteen women were elected in the first round of the election on February 26
and four more won seats in a runoff election Friday, adding to the boost of moderates and reformists in the next parliament.
Most of these women are aligned with Rouhani, said Reza Marashi, research director with the National Iranian American Council.
It will take more involvement of women to build a better future inside Iran, he said.
Not since the 1979 revolution have so many women been elected in Iran.
"This demonstrates the very important, very real and undeniable role women chart for the country," Marashi said.
The election of more women shows a public opinion shift into the moderate spectrum, away from the hard-line politics of Iran's past, said Harvard University scholar and Iranian-American Dr. Majid Rafizadeh.
"But their legislative power should not be overestimated," he said.
In the 290-seat parliament, they make up 6%.
"They're not in leadership positions and unlikely to change family laws with regards to women," Rafizadeh said.
The women all had to pass the test of the guardian council, which examines candidates' loyalties to the Islamic Republic.
"They're a product of the government and likely more loyal to the Islamic Republic than to the interests of their constituents," Rafizadeh said.
The new parliament takes over May 28, and experts agree it will give Rouhani a less hostile environment to push his reforms.