"If I Needed Someone" features prominent three-part harmony vocals and Rickenbacker twelve-string electric guitar – the instrument that the Byrds had adopted to replicate Harrison's sound in the 1964 film A Hard Day's Night.

The Hollies' success with the song gave Harrison his first chart hit as a songwriter, although his criticism of their performance led to a terse exchange in the press between the two groups.

[5] The two groups formed a friendship in early August 1965,[6] when the Byrds were enjoying international success with their debut single, a folk rock interpretation of Bob Dylan's "Mr. Tambourine Man", and Harrison and John Lennon attended their first shows in London.

[9][10][nb 1] In late August, the Byrds' Jim (later Roger) McGuinn and David Crosby met up with the Beatles in Los Angeles,[12] where they discussed with Lennon and Harrison the music of Indian sitarist Ravi Shankar and American Indo-jazz pioneer John Coltrane.

[13] The meeting led to Harrison introducing the sitar on Lennon's song "Norwegian Wood",[14][15] and to Crosby and McGuinn incorporating Indian influences into the Byrds' "Why"[13] and "Eight Miles High".

[40] Author Peter Doggett comments on Harrison's inspiration, in the context of the Beatlemania that continually encroached on the band's lifestyle: "'If I Needed Someone' may be the first pop song written from the jaded, though not quite exhausted viewpoint of a man who had women lined up outside his hotel door in every city of the world.

[42] On the fifth bar of each verse, a B melody-note sounds over a ♭VII triad – a chord that musicologist Dominic Pedler terms a G/A "slash" polychord, similar to that used at the start of "A Hard Day's Night".

[45] The verses retain an ascendant melodic quality due to the syncopated delivery,[44] the three-part harmonies in the vocal arrangement, and the constant bass figure.

[52] Further to the message of the song title, Harrison offers his love only if he should happen to need "someone", and on the condition that time allows for such a relationship; he conveys his feelings in matter-of-fact terms.

[58] Fontenot cites these lyrics as the reason why some commentators attach an alternative meaning to the song,[40] whereby the singer is already in a committed relationship and is addressing another woman, with the prospect of continuing a casual encounter.

[53][59][nb 6] In author Andrew Grant Jackson's reading, "[Harrison] was heading towards marriage with Pattie Boyd, so the lyrics address all the women of the world, saying that had he met them earlier, it might have worked out, but now he was too much in love (but give me your number just in case).

"[58] While considering that Harrison appears to be "playing his options, albeit gently", author John Kruth deems the line "Carve your number on my wall" to be "one of Rubber Soul's most enigmatic lyrics" and an evocation of the imagery in "Norwegian Wood".

[40] Jackson writes that the sound on "If I Needed Someone" was "so transcendent", in its combination of elements from the two Byrds songs and the Beatles' "soaring harmonies" and treble-rich guitar parts, that Lennon chose to use it for his Rubber Soul track "Nowhere Man".

[87] Beginning with the band's UK tour in December 1965, "If I Needed Someone" replaced "Everybody's Trying to Be My Baby", written by Carl Perkins, as Harrison's lead vocal spot in the Beatles' live shows.

[55][90][nb 10] In addition, with the group finding it increasingly difficult to replicate their studio recordings in concert,[92] it was one of only two Rubber Soul tracks that they performed live, the other being "Nowhere Man".

[104][nb 11] At this stage of their career, most of the Hollies' singles were written by outside writers,[108] yet the band were divided about whether to record a Beatles song, given the traditional rivalry between the two groups' hometowns, Liverpool and Manchester.

[111] In one of his articles covering the Beatles' concurrent UK tour, Alan Smith of the NME quoted Harrison as saying that the Hollies' version was "rubbish"[117] and that "the way they do their records, they sound like session men who've just got together in a studio without ever seeing each other before.

[102] In January 1966, at a press conference following his and Boyd's wedding, Harrison laughed off a reporter's question as to whether he had invited the Hollies to the ceremony, adding that the issue had "just got out of hand".

[125] Writing for Q magazine, John Harris recognised Rubber Soul as marking Harrison's "first decisive stride forward" as a songwriter, with "If I Needed Someone" suggesting for the first time that he could match the standard of Lennon and McCartney's work.

[126] Bruce Eder of AllMusic identifies the song as a "near-classic" written by Harrison during a period when his association with the Rickenbacker guitar had helped define the folk rock sound of groups such as the Byrds.

[128] Doug Collette of All About Jazz describes "If I Needed Someone" and "Think for Yourself" as "his most stylish tunes" and examples of Harrison's rise within the Beatles, although he highlights the guitarist's use of sitar on "Norwegian Wood" as a more creatively important contribution.

He cites "If I Needed Someone" as one of the tracks that, in their focus on modern, independent-thinking women, presented "complex and baffling females, much like the ones the Beatles ended up with in real life".

[131] In addition to admiring the group's performance, particularly the restraint Starr employs to resolve the tension created by the ♭VII chord change, Riley describes "If I Needed Someone" as "every guitarist's hook-bound fantasy".

[132][nb 14] Writing in Barry Miles' book The Beatles Diary, Peter Doggett considers it to be Harrison's best song "by far" up to that point, and he describes the group's harmony singing as "stunning" and "the tightest they'd yet achieved on record".

[145] On this 1991 live version, in Inglis' description, Clapton's "looping guitar solos" complement Harrison's vocal, which is more prominent than on the Beatles' original and sung in the style of Dylan.

[147] According to press announcements prior to the release in December 2002, Roger McGuinn recorded "If I Needed Someone" for inclusion on the multi-artist Harrison tribute album Songs from the Material World.

[152] In interviews to promote Limited Edition, McGuinn recalled Harrison's adaptation of the "Bells of Rhymney" riff as being "kind of a cool cross-pollination"[153] and said that it was "a great honor to have in some small way influenced our heroes the Beatles".

[152] In 2005, Nellie McKay recorded the song in the lounge jazz style for the multi-artist compilation This Bird Has Flown: A 40th Anniversary Tribute to the Beatles' Rubber Soul.