Yes.  You can apply for Social Security Disability benefits online by going to: http://www.socialsecurity.gov/applyfordisability/ and following the instructions.

You will find helpful links to the online forms you need to apply for disability benefits at www.socialsecurity.gov/applyfordisability. Reviewing and collecting the information shown in the Disability Starter Kit will help prepare you for your disability interview or to complete your online Disability Report.  The Disability Report Form (Social Security Administration-3368) asks for information about your conditions or impairments that prevent you from working. 

At this time, you cannot complete an application for Supplemental Security Income (SSI) disability online.  If you are filing for SSI disability, you can complete the Disability Report Form online. You can view the Fact Sheet and Checklist in the Disability Starter Kit to see what information you will need and the kinds of questions the Social Security Administration will ask when you have your disability interview in your local Social Security office or over the phone.