{{Infobox Saint
|name=Saint Eulalia of Mérida
|birth_date=ca. AD 290
|death_date=ca. AD 304
|feast_day=December 10
|venerated_in=Roman Catholicism
|image=John William Waterhouse - Saint Eulalia - 1885.jpg
|imagesize=200px
|caption=''Saint Eulalia'', by John William Waterhouse, 1885, Tate collection.
|birth_place= Mérida, Spain
|death_place=Mérida
|titles=Martyr
|beatified_date=
|beatified_place=
|beatified_by=
|canonized_date=
|canonized_place=
|canonized_by=
|attributes=cross, stake, and dove
|patronage=runaways; torture victims; widows<ref>[http://www.catholic-forum.com/saints/sainte06.htm Patron Saints Index]</ref>
|major_shrine=Cathedral of San Salvador
|suppressed_date=
|issues=
|prayer=
|prayer_attrib=
}}

'''Eulalia of Mérida''' was a Roman Christian child martyred in Emerita in Mérida in persecution of Christians in the reign of emperor Diocletian and his co-emperor Maximian.  Others place her death at the time of Trajan Decius (AD 249-51).<ref name="ox"></ref> There is some dispute as to whether Saint Eulalia of Barcelona, whose story is similar, is the same person.<ref></ref> 

Eulalia was a devout Christian virgin, aged 12–14, whose mother sequestered her in the countryside in AD 304 because all citizens were required to avow faith in the Roman gods.  Eulalia ran away to the law court of the governor Dacian at Emerita, professed herself a Christian, insulted the pagan gods and emperor Maximian, and challenged the authorities to martyr her.  The judge's attempts at flattery and bribery failed.  According to the Spanish-Roman poet Prudentius of the fifth century, she said:

:''Isis Apollo Venus nihil est,''
:''Maximianus et ipse nihil:''
:''illa nihil, quia factu manu;''
:''hic, manuum quia facta colit''

:(Venus are naught,
:Nor is Maximian anything more;
:Nothing are they, for by hand they were wrought,
:He, for of hands he the work doth adore)

She was then stripped by the soldiers, miraculous snow to cover her nakedness, its whiteness indicating her sainthood.   

right|250px|thumb|''Le martyre de Sainte Eulalie'', toile de [[John William Waterhouse, 1885]]
'''Sainte Eulalie de Mérida''' est une vierge martyre, célébrée dans un hymne de Prudence (''Peristephanon'' 3) et dans la célèbre ''Séquence de sainte Eulalie'', premier texte littéraire en français. 
Elle aurait dit après son jugement, au juge (dans plusieurs légendes hagiographiques, il s'agit du proconsul Dacien) :
::''Isis Apollo Venus nihil est,''
::''Maximianus et ipse nihil:''
::''illa nihil, quia factu manu;''
::''hic, manuum quia facta colit''

Plusieurs communes portent son nom (cf. Sainte-Eulalie). Dans de nombreux cas le nom d'''Eulalie'' a été modifié jusqu'à devenir méconnaissable : Saint-Aulaye (Dordogne), Saint-Aulaire (Corrèze), Saint-Aulais (Charente), Sainte-Alauzie (Lot), Saint-Araille (Haute-Garonne), Sentaraille (Ariège) et même Saint-Éloi (Ain).

Il existe une autre vierge martyre hispanique portant ce nom : sainte Eulalie de Barcelone.
(Homonymie : cf. Sainte Eulalie)