The proposal could disrupt the $20bn (Â£14bn) set-top box market by allowing companies like Apple and Alphabet to sell competing devices.
Currently US cable customers rent the boxes at an average of $231 a year, on top of cable TV charges.
The proposal sparked criticism from the already struggling cable TV industry.
Cable companies have seen their profits and customer bases hit by growing competition from online TV subscription services like Netflix and Hulu.
The FCC has said opening the set-top box market to smart TV and tablets will lower the price for consumers. The proposal requires cable companies to give alternative providers access to cable programming.
The regulators voted 3-2 in favour of moving ahead with the proposal which will now be opened to public comment.
A set-top box translates the codes sent from cable providers into pictures and sound that come through the TV. Some third parties already have this technology, but need to make private deals with cable companies to get access to programming.
The proposal sparked a wave of lobbying from both sides that forced the FCC to call off a Twitter "town hall" - open meeting - on Wednesday.
The US Federal Communications Commission (FCC) voted to move forward with a proposal to boost competition in the cable set top box industry.