[3] The municipality was named after the tree Phyllanthus acidus, which bears edible sour fruits.

[5][6] Iba was founded by the Order of Augustinian Recollect priests led by Rodrigo de San Miguel in 1611 as the village of Paynauen.

[7] The Aeta people settled in the hinterlands and the majority of them dwelled in the Mount Pinatubo area.

On August 28, 1901, American Civil Governor William Howard Taft held the historic session of the Second Philippine Commission establishing the Province of Zambales under the American rule held at Roman Catholic Church of Iba.

The LCP had tried to influence of former President Gloria Macapagal Arroyo to certify as call for immediate attention a draft of a law imposing a suspension on the conversion of additional towns into cities.[when?

[citation needed] Senator Sonny Angara advocated for House Bill 24 filed by Zamboanga Sibugay Representative Dulce Ann Hofer giving automatic cityhood to capitals of provinces without cities, and freeing the capital towns of provinces from the income needs of the cityhood.

[15][7] The majority of the people in Iba, Zambales are Roman Catholics second was the Aglipayan Church, The largest minority religion is Iglesia ni Cristo followed by various Protestant denominations.

The seat of the Ecclesiastical District of Zambales North of the Iglesia ni Cristo is located in Iba.

[citation needed] With a continuously growing number of commercial establishments, banks, and financial institutions in Iba, it contends among the most competitive municipalities in Philippines, and is pushing forward towards a progressive city.

Its pollution-free beaches due to the absence of industrial-polluting activities in the locality, make it one of the best places in the Philippines.

In response to the growing number of both local and foreign visitors, investments in beach resorts have increased in the last fifteen years.

[29] The provincial office of the Technical Education and Skills Development Authority (TESDA) in Zambales is located on Magsaysay Avenue.

TESDA was established by the Philippine government to manage and supervise the vocational education and skills development of the country's human resources through training and scholarships.

[30] All Asia Aviation Academy is a flying school offering flight and ground training located in Iba Airport between Brgy.