The resolution, which was introduced by Saudi Arabia, doesn't directly accuse Iran of involvement but calls on it "to comply with all of its obligations under international law" and to cooperate in "seeking to bring to justice" the people who allegedly plotted to kill the envoy.
The vote was 106 in favour, nine against and 40 abstentions.
India takes its obligations under the Convention on the Prevention and Punishment of Crimes against Internationally
Protected Persons Convention with utmost seriousness, India's Permanent Representative Hardeep Singh Puri said in an explanation of India's vote.
"However, we have abstained today on the resolution, as its substance deals with a specific case in which we are not in the possession of full facts and the matter is sub-judice," he said.
"India has been a victim of terrorism for decades," Puri said. "We condemn terrorism in all its forms and manifestations, and we have been in the forefront of global actions on counter-terrorism."
"Our tireless efforts as Chair of the Counter-Terrorism Committee, established under Security Council Resolution 1373, have resulted in the UN adopting a 'zero tolerance' approach towards terrorism. We urge all UN member-states to strive for the strict implementation of this approach," he said.
US officials in October accused Manssor Arbabsiar, a 56-year-old naturalised US citizen, and Gholam Shakuri, an Iran-based member of Iran's Islamic Revolutionary Guard Corps, of conspiring to hire hit men from a Mexican drug cartel to bomb a restaurant where the Saudi ambassador would have been.
Iranian Ambassador to the UN Mohammad Khazaee called it "mind boggling" that "an unsubstantiated claim of one member state with a long history of animosity against my country that my government has already and strongly rejected" served as a basis for the resolution.