What Does Dreaming of a Housefly Mean?
Traditional Interpretation
In the tradition of Ibn Sirin and al-Nabulsi, the fly represents weak but insistent people who cause constant irritation, gossips and lowly characters, and troubles that look small yet grind one down. The black housefly in particular can point to nuisances that plague your life and return however often you drive them off, to envious people, or to unlawful gain.
Psychological View
In modern psychology, the housefly can symbolize the small but constantly nagging anxieties accumulating in the unconscious, suppressed irritations, and the obsessive thoughts one "cannot shake off." This dream may be pointing out that you need to notice the energy-draining relationships in your life, or a matter you have been avoiding.
By Context
For a Single Person
Can indicate that there may be someone around you who gossips or whose intentions are not pure; it may point to the need to take your time and get to know people before forming attachments.
For a Married Person
Can point to outside interference aimed at disturbing the family's peace, to small arguments growing larger, or to worries about envy and the evil eye; patience and calm are counseled.
Seeing a Swarm of Flies (many Houseflies)
Can indicate that small troubles arriving one after another, a crowded but wearying circle, or accumulating responsibilities are exhausting you; taking them on one at a time may bring relief.
Driving Away or Killing the Housefly
According to Ibn Sirin, this can indicate that you will be freed of the person or trouble disturbing you, that you will drive off the distress upon you by your own will, and that you will find peace.