The National Institute for Health and Care Excellence says female patients should have free access to the drug, better known as an anti-wrinkle aid.
Some five million women in England and Wales have urinary incontinence, but many suffer in silence because they are too embarrassed to seek help.
Botox helps control the muscular bladder wall.
NICE says those with "overactive bladder syndrome" that has not responded to recommended lifestyle changes should be offered the injections.
It is not clear what causes it, but those affected by an overactive bladder have a frequent urge to urinate and can experience leakage before they can make it to the toilet.
Cutting down on caffeinated drinks such as tea and coffee, as well as alcohol, doing pelvic floor exercises and making scheduled trips to the toilet can help, but some people will need medical treatment or surgery.
The condition is different to stress incontinence - when the pelvic floor muscles are too weak, as can occur after childbirth, causing leaks with coughing and laughing.
With an overactive bladder, there is a problem with how the bladder responds to getting fuller, meaning the person feels they urgently need to urinate more often than most.
Someone with this condition might end going up to the toilet up to 15 times a day and three times a night, for example, when the norm is to go four to eight times a day and up to once a night.
It affects both sexes, but most often women. The NICE guidelines, which cover England and Wales, only discuss treating women.
Botox treatment is thought to help dampen chemical messages that your bladder uses to tell the brain that you need to urinate.
The injections are administered directly to the bladder wall via a small device inserted into the urethra - the tube you urinate through.
Clinical trials suggest this treatment may last for up to six months, but NICE says people also need to be aware of the possible side-effects.
The treatment can make it more difficult to pass urine and some people may find they need to use a catheter for a time. There is also a chance of getting a urine infection.
Anyone who starts on this treatment should have a face-to-face check up or be reviewed over the phone within four weeks, says NICE.
Prof Mark Baker, director of the Centre for Clinical Practice at NICE, said: "Urinary incontinence is a distressing condition affecting the lives of millions of women of all ages.
"While rarely life-threatening, it may seriously influence a woman's physical, psychological and social wellbeing.
"Over the years we have seen an increase in women seeking treatment, yet many others are still suffering in silence and not receiving the appropriate care for their condition.
"This updated clinical guideline suggests a range of treatments that women should be able to access to limit the distress that urinary incontinence can cause."
Botox injections can now be offered as a treatment for urinary incontinence, says England's NHS drugs watchdog.