Mattel Inc., the largest U.S. toy maker, said on Monday second-quarter profit rose 15 percent, helped by strong sales of its Wheels toys and Barbie dolls abroad.

Net income rose to $43.1 million, or 11 cents a share, from $37.4 million, or 10 cents a share, a year earlier.

Quarterly sales rose 6.5 percent to $1.02 billion from $957.7 million a year ago, as a 3 percent decline in U.S. sales was overshadowed by an 18 percent increase in international markets.

Analysts on average expected Mattel to earn 10 cents a share on $1.02 billion in sales, according to Reuters Estimates.

Sales of Mattel's girls and boys brands rose 5 percent, while Fisher Price sales rose 12 percent. The company's Wheels business, which includes Hot Wheels and Matchbox toy cars, increased 20 percent.

Worldwide sales of its 48-year-old Barbie line rose 6 percent as strong sales abroad overcame a decline in the U.S., where the dolls face competition from MGA Entertainment's Bratz dolls and Hasbro's Littlest Pet Shop.

(Reporting by Sarah Coffey and Martinne Geller)