The hosts scored once in either half to leave Wigan in the relegation zone and put another dent in the FA Cup finalists' survival bid.
A first Upton Park goal for Matt Jarvis and a Kevin Nolan volley secured the win, although the Hammers were second best for much of the second half with the Latics unable to make their dominance pay.
Wigan were the first side to threaten as Antolin Alcaraz fired straight at Jussi Jaaskelainen before Hammers skipper Nolan tried to open the scoring. He could not connect with a Gary O'Neil corner and saw his subsequent volley pushed clear by Wigan goalkeeper Joel Robles.
Shaun Maloney then put a free-kick just over the crossbar before Jarvis' cross from the left flank snuck inside Robles' far post.
Both James Collins and Mohamed Diame had shots blocked after the Latics' defence fell asleep before the break.
The visitors came out attacking with both Jordi Gomez and Arouna Kone having strikes within two minutes of the restart. Diame then saw a dipping effort gathered before Joe Cole replaced Ricardo Vaz Te on the wing.
Maynor Figueroa soon lofted a ball over the West Ham defence and Emmerson Boyce's diving header was kept out by Jaaskelainen.
Substitute James McArthur forced a art save out of the Finnish goalkeeper before Paul Scharner headed straight at him when free inside the area. But those worries were put to bed as Nolan latched on to Andy Carroll's pass to volley West Ham into a two-goal lead.
Carroll should have added a third himself after bursting into the area but he put his shot wide and Roberto Martinez's side are now three points adrift of safety with just five games remaining.
- Sports & Recreation
- Kevin Nolan
- Matt Jarvis