Salman had appealed before the Jodhpur bench of the high court challenging a lower court verdict in 2006 handing him a one and five-year term in the two separate cases of poaching.
Ghai, who shares a close bond with Salman, tweeted: "Acquittal (of) Salman Khan is (a) story of bad times (and) good times. I fully believe in our judiciary with many doors open to knock for fair justice".
Meanwhile, Varma expressed displeasure over the time it took for the verdict.
"Only celebrity cases make us realise how dead slow judiciary works. It's scary, it took 20 years for court to decide Salman Khan is not guilty," he tweeted.
Filmmaker Ashoke Pandit also congratulated Salman and his father and veteran lyricist Salim Khan.
Actress Shweta Rohira posted: "My happiness and relief knows no bounds today! Goodness wins! Love you bhai."
However, the news didn't go down well with some.
A post on an unverified page of actress Renuka Shahane on Facebook censured the judgment raising questions like "Who killed the black buck and the chinkaras? Did the driver kill them? Did nobody kill them? Do judges decide according to Buckworth-Lewis method? Who will pay for the mental torture that Salman has had to go through now that he has been declared not guilty? Doesn't the nation want to know the truth?"
Salman and the state government had appealed before the High Court challenging the lower court's verdicts on various grounds.
On Monday, Justice Nirmaljit Kaur while allowing Salman's appeal, acquitted him of all charges and also dismissed the state government appeal for enhancing the sentences.
The hearing was completed in the last week of May and the order reserved. Salman was accused of killing chinkaras in two separate incidents.
One animal was said to have been killed at Bhawad on the outskirts of Jodhpur on September 26, 1998 and the other at Ghoda Farms on September 28, 1998. He was shooting for the film "Hum Saath Saath Hain" at that time.
Salman was earlier lodged in the Jodhpur jail over the cases. Salman's sister Alvira was present in the jam packed court room when the judgment was pronounced.