It's the insects that are giant, not the films. The actors are usually the lesser characters, while the insects are the stars of the movie. Spiders are not insects, so you need to see the Spider film list for those. We're including ants, bees, cockroaches, worms, mosquitoes, and mutant bugs. This is the official Top2040 list of top 40 killer insect movies.
1 - The Mist (2007) based on Stephen King's novella, giant insects enter from another world.
2 - The Black Scorpion (1957) top-notch stop-motion effects with giant scorpions.
3 - Tremors (1990, Kevin Bacon) colossal earthworm-creatures trap the residents of a small town.
4 - Mimic (1997) Excellent movie about human sized insects living among us, mimicking us.
5 - The Deadly Mantis (1957) classic film! Scientists release a frozen giant mantis in the Arctic. It flies to New York and terrorizes the city.
6 - Phase IV (1974) An organized hive of ants takes over a science lab, and then a whole town. One of the best insect movies of all time; by far the best ant film.
7 - Them! (1954) This time the ants are huge!
8 - The Swarm (1978) an invasion of killer bees.
9 - Starship Troopers (1997) alien space bugs wage war on the universe.
10 - Creepshow (1982) in the 5th story "They're creeping up on you!" cockroaches take over an apartment.
11 - The Fly (1958) Vincent Price's original masterpiece about a man turning into a fly.
12 - Empire of the Ants (1977) written by H.G. Wells. Organized giant ants have taken over the Florida everglades.
13 - Swarmed (2005) swarms of killer bees
14 - Bug (1975) an earthquake releases carnivorous roaches which attack a city.
15 - Skeeter (1993) killer mosquitoes on the loose!
16 - Bug Buster (1998) mutant roaches vs. Randy Quaid and the cast from Star Trek TOS.
17 - The Fly (1986) Jeff Goldblum in the remake of the classic "The Fly."
18 - Black Swarm (2007) supersonic killer bees
19 - The Food of the Gods (1976) Giant Wasps, chickens and rats! What more could you want?
20 - Star Runners (2008) Alien insects; good sci-fi movie!
21 - Attack of the Giant Leeches (1959) low budget, high fun.
22 - Infestation (2009) Giant insects take over the world in this post-apocalyptic dark comedy about alien insects, spiders and zombies, and a few mutant hybrids.
23 - Deadly Stingers (2003) toxic waste makes giant scorpions.
24 - Mosquito (1995) a spaceship crashes in a swamp in the U.S., and mosquitoes feed on the alien corpses, causing them to grow to the size of carnivorous birds.
25 - Killer Bees (2008) one of 4 bee movies with this same title.
26 - Slither (2006) space slugs turn people into zombies
27 - Killer Bees (1974), yep, another swarm of bees.
28 - High Plains Invaders (2009) The insects look cool, the script … not so much.
29 - Glass Trap (2005) Radioactive ants trap people in a skyscraper.
30 - Highly Dangerous (1950) A spy movie involving germ warfare, using bugs as carriers.
31 - Mongolian Death Worm (2010) giant creatures attack the crew of an oil drilling plant.
32 - Stinger (2005) a big queen scorpion takes on the crew of a US naval ship. Bad acting, cool insect.
33 - Dragon Wasps (2012) very big wasps vs. the US Army in the jungles of Belize.
Best novel with giant bugs: Earthweeds
See also: Top-20 Post-Apocalyptic Novels with Giant Lizards and Spiders
34 - Ticks (1993) Giant ticks take down Seth Green and Clint Howard.
35 - The Nest (1988) Cockroaches take over an island community.
36 - Mansquito (2005) a psycho prisoner is transformed into a giant mosquito.
37 - Centipede (2004) trapped in underground caves with a giant centipede
38 - Tail Sting (2001) genetically altered scorpions
39 - The Wasp Woman (1959) she's a beauty queen by day, and a queen bee by night!
40 - Evil Spawn (1987) Alien bug from Venus
Bonus: 41 - Slugs (1988) killer slugs go after a small community. Bad acting and gratuitous nudity make this a real Oscar contender, but somehow it didn't win.
Also check out other lists at www.top2040.com
Honorable Mention: King Kong (2005) had some spiffy giant roaches on the island.
In "Joe's Apartment" the cockroaches talked - very disturbing movie. The only thing creepier than bugs in movies, is talking ones.