The loss of $27.33 per share is the third-worst quarterly loss in the automaker's history. In the same period a year earlier, GM recorded a net profit of $891 million, or $1.56 per share.
Revenue for the April-June period was $38.2 billion, down $8.5 billion from a year earlier.
The company said its loss included $9.1 billion in one-time charges, including $3.3 billion for the buyouts of 19,000 U.S. hourly workers who left at the end of June and $2.8 billion in liabilities related to Delphi Corp., its former parts division.
It also included $1.3 billion worth of write-offs because of a decline in the value of GMAC Financial Services' portfolio of trucks and sport utility vehicles, which have seen sales have plummet due to high gas prices.
GM also took a $197 million charge related to the settlement of a nearly three-month strike at supplier American Axle and Manufacturing Holdings Inc., which shut down more than 30 GM plants. GM agreed to help American Axle fund worker buyouts as part of the settlement.
Without the one-time charges, GM lost $6.3 billion, or $11.21 per share. Twelve analysts surveyed by Thomson Financial predicted a $2.62 per share loss on revenue of $44.57 billion.
The $15.5 billion loss is less than half GM's record $38.6 billion loss in the third quarter of last year. That loss was due to a write-down on the taxable value of assets. The second-worst loss was $21 billion in the first quarter of 1992.
GM said its revenues outside North America rose by $1.7 billion to $20.8 billion in the quarter, but those gains were more than offset by losses in North America, where high gas prices and the weak economy have wreaked havoc on the auto industry.
On July 15, GM announced plans to lay off thousands of hourly and salaried workers, speed the closure of truck and SUV plants, suspend its dividend and raise cash through borrowing and the sale of assets.
"As our recent product, capacity and liquidity actions clearly demonstrate, we are reacting rapidly to the challenges facing the U.S. economy and auto market, and we continue to take the aggressive steps necessary to transform our U.S. operations," GM Chairman and Chief Executive Rick Wagoner said in a statement.