According to Official Guinness Records,
The largest bar of soap weighs 14.45 tonnes and was achieved by Jinan Rujia Co., Ltd. (China) in Jinan, Shandong, China on 11 December 2015.The soap took over 3 months to complete and was divided up in to smaller pieces after the attempt to be sold.
For a complete list of 2015 records, please visit 2015 Guinness Records in China.