Mr. W.H. is a person known only by his initials, to whom the first edition of William Shakespeare's sonnets (1609) was dedicated:

To the onlie begetter of
These insung sonnets
Mr. W.H. all happinesse
And that eternitie
Promised
by
Our ever-living poet
Wisheth
The well-wishing
Adventurer in
Setting
Forth

The mystery of his identity has tantalized generations of biographers and critics, who have generally argued either that W.H. was also the “fair youth” to whom many of the sonnets are addressed or that he was a friend or patron who earned the gratitude of one or both parties by procuring Shakespeare's manuscript for the printer, Thomas Thorpe. Among the names offered for consideration are those of Henry Wriothesley, 3rd Earl of Southhampton, who was a noted patron of several writers, and William Herbert, 3rd Earl of Pembroke, with whom Shakespeare is believed to have had some connection, albeit slight. Also suggested are William Hatcliffe, who was Lord of Misrule during the celebrations at Gray's Inn (1587–88), and William Hall (a printer) and Sir William Harvey, both of whom could well have conveyed the manuscript to Thorpe. The ambiguity with which the dedication is expressed presents additional problems, for apparently the person in question was both “wished” eternity by Thorpe and “promised” it by Shakespeare.