Hutchinson Telecom is looking to get the go-ahead from Walsall Council planners to erect the 15-metre pole and associated equipment on a grass verge on Stroud Lane.
But people living near the location said they are concerned about the potential health issues and their properties being devalued.
They said an application for a slightly bigger mast around five metres away from this location was refused last year.
The mast will service Three network customers, and the company moved to reassure people the mast is safe and will support businesses and residents in the area.
George Cross, who has so far collected more than 70 signatures on a petition against the mast, said: “The decision to refuse last year was based on the visible impact that this will have.
“It is huge and almost twice as high as houses in the area. And they refused it based on policy that it shouldn’t be acceptable in an area where there is low rise residential properties.
“Although the new application is a little different, I think it should be refused if planners are going to be consistent about their decisions.
“There are concerns of many residents of the health implications of something like this. It’s neither proven or unproven I think.
“This is going to be very tall and where we sit in the garden, this is near four or five metres. So health is a big concern.
“In addition to that, the likelihood of it devaluing our properties is realistic.
“We have collected more than 70 signatures on a petition so there is a strong feeling this shouldn’t be in this place.
“There is a counter argument of course that we all use mobile phones and technology and these things are needed.
“And I agree with that but not in this particular location at the bottom of people’s gardens. There are better places.”
Ward councillor Sarah-Jane Cooper added: “Residents are rightly concerned about the proposals as set out. No one would want to see a mast of this size directly outside of their homes.”
Her colleague Councillor Josh Whitehouse said: “It has been great to see the community come together to oppose these proposals and we really hope that they are successful.
“Residents deserve to have their views heard and taken into consideration.”
A Three spokesperson said: “5G rollout is vital for residents and businesses of Willenhall. We want to offer the community a reliable network experience and a new site will be critical to making that happen.
“While we try to keep mast sites as unobtrusive as possible, they do need to be situated where people will be using the service and, in many cases, in precise locations to ensure the widest breadth of coverage.
“The 5G rollout by all UK MNOs complies with all global standards on health and safety which have been developed since the early 1990s – you can see recent independent testing from Ofcom and find more information via #5gcheckthefacts on social media.”
Residents have until June 29 to give their views and planners are expected to make a decision on August 1.