Flies are one of the few downsides to summer, but having the best fly spray for horses makes a huge difference. Insects aren't just a pest – some of their bites can cause reactions, infection, and constant itching, so it's crucial to keep your horse protected.
By investing in a high-quality option, like our selection below, you won't have to keep reapplying or worry about insects bothering your horse. You don't have to spend a fortune either – some of these can be diluted with water to make them stretch further and last longer.
To help you pick the best option, the experts over at our sister site Horse & Hound have rounded up their top picks below after thorough research and testing. Keep reading to find out why they voted the Farnam Tri-Tec 14 as the winner!
The best fly spray for horses
Best fly spray for horses overall
This water-based spray offers long-lasting protection against flies, gnats, mosquitoes, and ticks, with active ingredients that remain effective for up to 14 days after application.
After testing it for five weeks on her pony Frankie and around the stable area, our tester Alex was impressed by its powerful formula and how evenly the spray nozzle distributed the product. It successfully repelled flies during hacks and when Frankie was turned out in the field.
While the spray is a little pricier than other products we've tested, Alex says "a little goes a long way."
PetsRadar editor Georgia also uses this fly spray on her horse.
“My horse lives out, and this only needs reapplying around once a week – unless I wash him off. One 32oz bottle lasts me all summer, which makes it great value,” she says.
If you want your money to go even further, opt for the UltraCruz Natural Horse Fly & Tick Spray, which costs just $0.37 per ounce.
Reasons to buy: Powerful, long-lasting, sprays evenly, smells nice
Reasons to avoid: A little expensive, strong chemicals, not licensed for direct use on horses in the UK
Runner-up fly spray for horses
Come rain, shine, or sweat, this water-resistant fly spray will keep your pony protected against insects in all conditions and works for up to two weeks after application.
The formula contains a powerful trio of cypermethrin, pyrethrins, piperonyl butoxide, and butoxypolypropylene glycol, which quickly kill and repel insects like flies, mosquitoes, deer ticks, gnats, ticks, and lice that can cause discomfort and disease to your horse.
Farnam Endure comes in a refillable spray bottle that’s easy to use, and topping it up (rather than rebuying) works out slightly cheaper by the gallon – $0.78 per ounce instead of $0.98 per ounce.
For something even more affordable, we'd recommend the UltraCruz Natural Horse Fly & Tick Spray.
Reasons to buy: Water-resistant, refillable bottle, long-lasting protection
Reasons to avoid: A little expensive, reapplication needed for heavy rain or washing, not licensed for direct use on horses in the UK
Best weather-resistant fly spray for horses
This hard-working formula protects your horse from more than 70 insect species, including flies, mosquitoes, ticks, gnats, and ants. Thanks to UltraBond Technology, it can withstand tough weather conditions for up to 17 days and also contains sunscreen and conditioner.
So, how did it perform when tested? Alex tried the previous version of this spray (Absorbine UltraShield Insecticide) for three months and said it deterred pests "extremely well" – even when her horses got sweaty in hot weather.
She was impressed with the spray’s thick, even mist and how robust the bottle was, having dropped it multiple times without any leaks. It adhered well to surfaces, lasted a long time – offering good value for money – and had a pleasant smell.
This isn’t licensed for direct use on horses in the UK, so you might want to opt for Absorbine UltraShield Insecticide if that’s important to you.
Reasons to buy: Weather-proof, contains sunscreen and conditioner, long-lasting
Reasons to avoid: Not licensed for direct use on horses in the UK
Best natural fly spray for horses
Want to avoid harsh chemicals and pesticides? This all-natural formula contains ingredients like clove extract, peppermint oil, and citronella oil to ward off pesky bugs, including flies, ticks, mosquitoes, and gnats.
This spray costs just $0.37 per ounce and also comes in an even cheaper one-gallon bottle that can be used for refills, making it one of the cheapest products in this guide.
While it has a lower price tag than other products we’ve tested, you’ll need to apply it every day, and it won’t withstand rain or sweat like Absorbine UltraShield EX Insecticide does. It’s also worth bearing in mind that it only repels insects rather than killing them.
Reasons to buy: Natural ingredients, affordable
Reasons to avoid: Needs daily application, not long-lasting, not licensed for direct use on horses in the UK
Best affordable fly spray for horses
When this concentrated formula is mixed with water, it works out at just $0.20 per ounce, making it the most affordable option in this guide. It repels a long list of insects, including gnats, mosquitoes, and ticks – and kills them on contact.
Since you'll need to reapply the solution every three to four days, it's not as long-lasting as some of the other products we've tested, but we think it's a strong contender based on the high-quality ingredients and affordability alone.
You'll need to invest in some reusable spray bottles to decant the diluted product into, but these ones from Amazon are inexpensive and come in a multipack that will last you a while. If you'd rather not mix it yourself, it's also available in a ready-to-use spray bottle, though it will cost you slightly more.
Reasons to buy: Cheap, effective formula
Reasons to avoid: Has to be diluted, needs reapplication every few days, not licensed for direct use on horses in the UK
Photos from testing
Other fly sprays for horses to consider
Leovet Power Phaser Fly Spray
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Crowned as the best fly spray for horses by the Horse&Hound team, we highly recommend this product if you can get your hands on it.
The only reason it didn’t make the top five is because it’s not readily available in the US, unfortunately. Alex said it’s one of the best sprays she’s ever used, thanks to the reliable formula that withstood hacks on warm evenings and schooling on cooler mornings, and prevented any insects from bothering her horses.
However, she did notice that the spray came off when her horses sweated a lot, and that the smell was strong and noticeable.
How we tested the best fly sprays for horses
These products were tested by Georgia Guerin (Editor of PetsRadar and Head of Ecommerce at Horse&Hound) and Alex Robinson (Showing Editor at Horse&Hound) for a minimum of three weeks.
When reviewing the products, the following criteria were kept in mind:
- Effectiveness: How well did the product repel and kill insects?
- Longevity: How long did the spray work before needing reapplication? Did it withstand sweat and harsh weather conditions?
- Application: How easy was the formula to apply?
- Scent: Did it have any unpleasant smells worth noting?
- Value for money: Is it affordable and worth the price tag?
- Packaging: Is it leak-proof and durable?
For more information about our processes, read how PetsRadar tests and how Horse&Hound tests.
Who tested the best fly sprays for horses?
How to choose the best fly spray for horses
With so many options on the market, it can be difficult to know which fly spray to choose. To help you make an informed decision, we asked veterinarian Dr. Lisa Coder for her advice:
She says: "When choosing a fly spray, there are many factors to consider. Oil based sprays last longer, but can be more drying or irritating to horses who have sensitive skin.
"Water based sprays are much gentler on the skin, but do not hold up against sweat, rain, or rinsing. Neither spray will last if a horse is bathed with soap.
"All natural products often use essential oils and other natural plant oils as repellents. These products are generally not as effective, and will need to be reapplied more frequently. Be sure to check with your veterinarian, as some essential oils can be toxic to horses."
Here’s a reminder of the best fly sprays for horses that we recommend:
Model | Price | Price per ounce | Protection duration |
|---|---|---|---|
$29.99 | $0.93 | Up to 14 days | |
$31.49 | $0.98 | Up to 14 days | |
$103.19 | $0.80 | Up to 17 days | |
$11.96 | $0.37 | Up to one day | |
$145.99 | $4.56 ($0.20 when diluted) | Up to four days |
What's the best way to keep flies off horses?
We know that the best fly sprays for horses keep those irritating insects at bay, but are there any other methods you can try as well? We asked Dr Coder for her thoughts.
She says, "The best way to keep flies off of horses is to reduce the flies in your facility. This means keeping stable areas clean and dry, removing feces daily at a minimum, and keeping stall waste as far from horse areas as possible.
"Another way to prevent flies on horses is to keep a barrier between your horse and the flies. This can be in the form of fly sheets and boots, screens on barn and stall doors, and use of facility fly sprays."
How often should you spray horses for flies?
When it comes to protecting your horse from insects, you might wonder how often you need to reapply the spray. According to Dr Coder, this all depends on:
- The type of spray used
- Other protections your horse has against flies
- How often your horse sweats
- How often your horse is bathed
Read next: Best fly rugs for horses and tips for taking care of your horse
Megan Milstead has been a staff writer at PetsRadar since 2023, covering buying guides, reviews, deals, and features. She grew up riding ponies and enjoyed competing in showing competitions across the UK. She holds a degree in Journalism from the University of Westminster, an Extended Diploma in Journalism from West Herts College, and is currently completing a pet behavior course through the University of Edinburgh. If you have any questions about the products featured in this guide, her emails are always open!
Dr. Lisa Coder graduated from the University of Missouri in 2013. Since then, she has worked in many different types of clinics, from equine, to mixed animal, to ER. She even served a few years with the United States Department of Agriculture as a public health veterinarian. She loves all animals and strive to provide a safe, comfortable, and compassionate place for the people and pets who make up our community family. Dr. Lisa and her practice Vital Animal Veterinary Clinic serves the greater Sioux Falls, South Dakota area, with compassionate care for cats, dogs, small exotic mammals, and reptiles. She is currently pursuing board certification in both types of exotic medicine. She has an absolutely brilliant staff, who supports her love of learning, teaching, and endeavoring to continually improve.
Edited by Georgia Guerin and Alexis De Leaver.
We regularly review our buying guides to ensure the products are relevant, available and up to date. This page was last updated in August 2025 by Megan Milstead.
