The Treasury Select Committee said Mr Diamond's evidence on the Libor fixing scandal had fallen well short of the standards expected by Parliament.
The MPs criticised Mr Diamond as they published the initial findings of a probe into the circumstances surrounding the fixing of the Libor rate, which sets inter-bank lending prices.
Mr Diamond said he was disappointed and strongly disagreed with several of the committee's statements.
"In particular, I strongly challenge certain assertions about my testimony," he said.
"On July 4, I appeared before the Committee voluntarily and on short notice.
"I answered every question that was put to me to me truthfully, candidly and based on information available to me.
"I categorically refute any suggestion to the contrary.
"I take particular issue with the attacks on Barclays' culture and character.
"Barclays, one of the only major UK financial institutions that did not need a rescue from the UK Government, is a tremendous institution with an over 300-year tradition of supporting economic growth and the communities in which we live and work.
"I am proud of what we accomplished over the 16 years I was employed there and our prudent management of the institution helped avoid the fates that befell other UK banks in 2009."
The Commons Treasury Select Committee said in its report that the Libor scandal had done great damage to the UK's reputation, reducing public trust in banks to an all-time low.
And it accused Mr Diamond of being "highly selective" in his evidence to it.
"Select committees are entitled to expect candour and frankness from witnesses before them," the report says.
"Mr Diamond's evidence, at times highly selective, fell well short of the standard that Parliament expects, particularly from such an experienced and senior witness," it added.