According to the United States Library of Congress Country Studies:
The war was militarily inconclusive; each side held prisoners and some territory belonging to the other. Losses were relatively heavyon the Pakistani side, twenty aircraft, 200 tanks, and 3,800 troops. Pakistan's army had been able to withstand Indian pressure, but a continuation of the fighting would only have led to further losses and ultimate defeat for Pakistan. Most Pakistanis, schooled in the belief of their own martial prowess, refused to accept the possibility of their country's military defeat by "Hindu India" and were, instead, quick to blame their failure to attain their military aims on what they considered to be the ineptitude of Ayub Khan and his government.
TIME magazine reported that India held 690 mi2 of Pakistan territory while Pakistan held 250 mi2 of Indian territory in Kashmir and Rajasthan. Additionally, Pakistan had lost almost half its armour temporarily. The same article stated that -
Severely mauled by the larger Indian armed forces, Pakistan could continue the fight only by teaming up with Red China and turning its back on the U.N.
Devin T. Hagerty wrote in his book "South Asia in world politics"
The invading Indian forces outfought their Pakistani counterparts and halted their attack on the outskirts of Lahore, Pakistan's second-largest city. By the time United Nations intervened on September 22, Pakistan had suffered a clear defeat.
In his book "National identity and geopolitical visions", Gertjan Dijkink writes
The superior Indian forces, however, won a decisive victory and the army could have even marched on into Pakistani territory had external pressure not forced both combatants to cease their war efforts.
An excerpt from Stanley Wolpert's India,summarizing the Indo-Pakistani War of 1965, is as follows:
In three weeks the second Indo-Pak War ended in what appeared to be a draw when the embargo placed by Washington on U.S. ammunition and replacements for both armies forced cessation of conflict before either side won a clear victory. India, however, was in a position to inflict grave damage to, if not capture, Pakistan's capital of the Punjab when the cease-fire was called, and controlled Kashmir's strategic Uri-Poonch bulge, much to Ayub's chagrin.
In his book titled The greater game: India's race with destiny and China, David Van Praagh wrote
India won the war. It gained 1,840 square kilometers of Pakistani territory: 640 square kilometers in Azad Kashmir, Pakistan's portion of the state; 460 square kilometers of the Sailkot sector; 380 square kilometers far to the south of Sindh; and most critical, 360 square kilometers on the Lahore front. Pakistan took 540 square kilometers of Indian territory: 490 square kilometers in the Chhamb sector and 50 square kilometers around Khem Karan.
Dennis Kux's "India and the United States estranged democracies" also provides a summary of the war.
Although both sides lost heavily in men and materiel, and neither gained a decisive military advantage, India had the better of the war. New Delhi achieved its basic goal of thwarting Pakistan's attempt to seize Kashmir by force. Pakistan gained nothing from a conflict which it had instigated.
"A region in turmoil: South Asian conflicts since 1947" by Robert Johnson mentions
India's strategic aims were modest it aimed to deny Pakistani Army victory, although it ended up in possession of 720 square miles of Pakistani territory for the loss of just 220 of its own.
An excerpt from William M. Carpenter and David G. Wiencek's "Asian security handbook: terrorism and the new security environment"
A brief but furious 1965 war with India began with a covert Pakistani thrust across the Kashmiri cease-fire line and ended up with the city of Lahore threatened with encirclement by Indian Army. Another UN-sponsored cease-fire left borders unchanged, but Pakistan's vulnerability had again been exposed.
English historian John Keay's "India: A History" provides a summary of the 1965 war
The 1965 Indo-Pak war lasted barely a month. Pakistan made gains in the Rajasthan desert but its main push against India's Jammu-Srinagar road link was repulsed and Indian tanks advanced to within a sight of Lahore. Both sides claimed victory but India had most to celebrate.
Uk Heo and Shale Asher Horowitz write in their book "Conflict in Asia: Korea, China-Taiwan, and India-Pakistan"
Again India appeared, logistically at least, to be in a superior position but neither side was able to mobilize enough strength to gain a decisive victory.
