Transport Minister Anthony Loke said these changes were in response to demands from motorists who want darker windows to block the sun and heat from vehicle cabins.
The changes are also in line with the UN Regulations on safety glazing materials installation on vehicles (UN Regulation No. 43).
However, front windshields, as well as the driver and front passenger side windows need to remain transparent, allowing 70% and 50% light through respectively for safety reasons.
Previously, rear car windows tints had to allow at least 30% of light through.
It is also possible for motorists to have all windows fully tinted for security and health reasons, but permission is needed to do so.
He said those who want this for security reasons would be charged a RM50 service fee for each application.
If their application is approved, they would be charged RM5,000 for a permit to have all their car windows fully tinted.
"Each approval will last for two years, and they need to reapply each time," he said, adding that the approval would be determined by a special committee headed by RTD director-general Datuk Seri Shaharuddin Khalid, which will meet monthly.
Many fear crime rate will go up with darker windows
30% VLT is dark enough, say auto accessories traders
The committee will vet each application and do cross checks with the police to determine if applicants have a clean record and no outstanding summonses.
However, those applying to have all windows fully tinted for health reasons are exempt from charges.
The new regulations come into effect on May 8 and will only apply to private vehicles, including those used for e-hailing services.
Road Transport Department (RTD) enforcement officers will start their checks on vehicles under the new regulations in three months.