Lenell John-Lewis scored the only goal as Grimsby climbed from seventh to second in the Conference table.
The striker finished well to score his ninth goal of the season midway through the second half after the ball dropped to him in the area.
John-Lewis had been denied a first-half opener by Braintree keeper Nick Hamann, who also saved from Craig Clay.
Grimsby are now unbeaten in six league matches but mid-table Braintree have not won for nine league games.
Grimsby Town boss Paul Hurst told BBC Radio Humberside:
"It's about time. Hopefully that can be a sign that this season might end differently for us. Obviously a long way to go but ultimately it was nice to come here and I think that's the best the pitch has been which helps.
"For me that's a great victory and one that is a sign that you've got a chance of doing very well, because for anyone who watched this game tonight and thought it was going to be a classic, it was never going to be that.
"Sometimes fans are quite close to you on that dugout and one or two were getting a bit uptight with some passes that went astray and things like that but ultimately it was about us being nice and solid and I don't think we looked like conceding."
- Published7 June 2019
- Published20 June 2016
