A selective breed, not a social butterfly
Some Belgian Malinois live peacefully with other dogs for life; others want nothing to do with unfamiliar dogs at all. What you rarely get is the oblivious, happy-go-lucky sociability of a young Labrador. The Malinois was bred to work closely with one handler and to react fast and decisively to his environment, so strange dogs are usually assessed, challenged, or ignored rather than greeted. Anyone choosing this breed for a multi-dog household should plan on managing relationships, not assuming them.
Where friction usually starts
Three patterns cause most trouble. First, arousal: Malinois play runs hard and fast, and a game of chase can tip into a scuffle when one dog will not de-escalate. Second, maturity: a puppy who loved every dog at five months can become selective or same-sex intolerant between one and two years old, which surprises owners who thought socialization had settled the question. Third, resources: toys, food, and the owner's attention are all worth competing for in a breed this intense, so shared living works best with separate feeding, duplicated high-value items, and structured together-time. Keep a written note of which pairings, settings, and resources have caused tension for this particular dog, because Malinois social problems are usually predictable once somebody bothers to record the pattern instead of relying on memory after a scare.
Introductions that give a Malinois a fair chance
Start on neutral ground with a parallel walk — two handlers, two leashed dogs, moving in the same direction at a distance where the Malinois notices the other dog but can still take food and respond to his name. Close the distance over several sessions, not several minutes. Let the first off-leash meeting happen in a large, boring space with no toys or food bowls present, and keep it short enough to end while both dogs are still relaxed. At home, give the new pairing weeks of gated separation and supervised contact before anyone sleeps loose together.
Living with a resident dog
A stable, confident resident dog of the opposite sex is usually the easiest match, and a senior dog deserves protection from a young Malinois's relentless invitations to play. Rotate rest time in crates or separate rooms so neither dog has to negotiate all day. Watch body language rather than hoping dogs sort it out: hard staring, freezing over a toy, and one dog repeatedly blocking the other's path are information, not dominance theater, and they mean the management plan needs tightening before a fight makes the point more loudly.
The dog-park question
Busy off-leash parks stack every trigger this breed has — sprinting strangers, rude adolescents, contested toys, no exits — so most experienced Malinois owners skip them and use training, hiking, and controlled playdates with known dogs instead. That is not a failure of socialization; it is matching the dog's social life to the dog he actually is. If a Malinois moves to a new home, KinsLe Transferrable Profiles keep his known dog preferences and past pairing notes attached to him, which spares the next household from learning his limits by trial and error.