The spot by Mother tells listeners they should not look at computers or screens before bed because the blue light they produce gives the brain the false impression of being awake.
Instead, it says people should read a magazine by lamplight because the yellow light is "sleepy cozy".
"Yellow" impressed Emma de la Fosse, the judge, by offering "genuine, useful, interesting tips".
Fosse, who is also the chief creative officer at OgilvyOne, said: "‘Yellow’ took the top position of the campaign simply because I couldn't resist the line ‘remember, a magazine is simply a paper version of the internet’.
"This is a well-written campaign, lifted further by good production."