In two of the cases, the men were in cars; in the other two, the suspects were on foot, police spokeswoman Margo Rohrbacher said.
The most recent incident happened Tuesday. A female juvenile was walking to her house in the 300 block of D Street at about 5 p.m. when a man followed her and loitered in the area for a short time, Rohrbacher said.
The man was described as white and about 6 feet tall with a mustache and muscular build. He was wearing a black T-shirt and jeans.
The three other incidents happened Saturday.
In the first, a man approached two women walking in the 800 block of Fourth Street at about 1:25 a.m.
As the women walked past the man, he suddenly grabbed one woman by the wrist and reached his hand inside the front of her pants, Rohrbacher said. The women ran away and called police.
That suspect is white and between 5 feet 8 inches tall. He was wearing a black baseball cap and black hooded sweatshirt.
Police also received two separate reports on Saturday of a man stopping his car next to female juveniles and asking them to get into the car, Rohrbacher said.
In one of those incidents, which happened in the area of Second and B streets at about 5:15 p.m., the suspect was a dark-skinned man in his 60s wearing a baseball cap and driving a silver Honda CRV, Rohrbacher said.
The juvenile walked away after the driver asked her to get into the car.
The second incident involved a Hispanic man in his 40s who stopped his pickup truck, which had a camper, in the area of 360 Third St. at about 8:15 p.m., Rohrbacher said.
The driver asked the juvenile to get into his truck. The girl walked away but the driver continued to circle the block until he was confronted by one of the girl's friends, Rohrbacher said.
Anyone with information about the incidents is asked to call San Rafael police at (415) 385-3000 or Crime Stoppers at (800) 222-8477.
Callers may remain anonymous and may earn a reward. Tips can also be made at www.bayareacrimestoppers.com.