Additional Sessions Judge SKS Razvi also acquitted Mr Tiwari's brother Ankur of the charges of threatening the complainant.
Mr Tiwari, a playback singer, was arrested in May 2014 by suburban Versova police in the case. He was later released on bail.
The complainant, allegedly his former girlfriend, had claimed that he raped her on several occasions between October 2012 and December 2013 after promising to marry her, but did not keep the promise.
"The prosecution could not prove its case," said Mr Tiwari's lawyer Rizwan Merchant.
The complainant didn't support the prosecution case during her testimony in the court and was declared 'hostile witness'.