Blockley Lodge No. 6345 in the register of the United Grand Lodge of England is a masonic lodge in the City of Oxford and in the Masonic Province of Oxfordshire. It is also the University Lodge for Oxford Brookes University and is a participating member of the Universities Scheme.

Lodges of operative masons (stonemasons) had existed in Oxfordshire and throughout Britain since the Middle Ages. In Oxford, records from 1391 note the existence of a magister lathomus liberarum petrarum (Latin: 'a master mason of freestones'). Freestone is a grainless sandstone or limestone suitable for ornamental carving. The first evidence of non-operative or speculative masons (men who were not stonemasons) joining masonic lodges in England dates from 1646, although the practice almost certainly began earlier. In Scotland, the documentary evidence of this practice dates to 1634, but probably began a century earlier. The first Grand Lodge of England (and in the world) was founded in 1717. It became the United Grand Lodge of England in 1813.

Blockley Lodge's own history began when it was granted a Warrant from the United Grand Lodge of England on 7 August 1946. It traces its masonic lineage in Oxford back to Alfred Lodge No. 340 which was granted its Warrant by Grand Lodge on 16 February 1814, the first Warrant granted by the newly United Grand Lodge of England. Members of Alfred Lodge in turn founded Apollo University Lodge No. 357 (granted a Warrant on 21 December 1818), the lodge for present and past matriculated students of the University of Oxford. Alfred Lodge members also founded Bertie Lodge No. 1515 which was granted a Warrant on 20 October 1874. Bertie Lodge members then founded Isis Lodge No. 4242, based in Abingdon, which was granted its Warrant on 19 January 1921. Twenty-five years later, Isis Lodge members founded Blockley Lodge No. 6345.

The first meeting of Blockley Lodge was on the date of its consecration on 24 September 1946. Since then, Blockley Lodge members became the founders of another Oxford lodge, Saint Giles Lodge No. 8904, which was granted its own Warrant on 31 January 1980. All of the lodges in the Masonic lineage of Blockley are still active and together they represent over two hundred years of Masonry in Oxford. 

Blockley Lodge is named in honour of the Revd T.T. (Thomas Trotter) Blockley (22 May 1864 - 2 March 1950). T.T. Blockley attended the Harrow School, then went up to Magdalen College, University of Oxford, graduating with his BA in 1887 and MA in 1890. He became a Mason while at Oxford in the Apollo University Lodge. After serving as a curate at St Alban's Cathedral in Hertfordshire, he returned to Oxford and was appointed Dean of Divinity (chaplain) of Magdalen College where he served for fourteen years (1897-1911). He was made Grand Chaplain of the United Grand Lodge of England in 1918 and towards the end of his masonic and clergy careers he was Provincial Grand Master for Oxfordshire in 1945, aged 81. Due to the Lodge's historic connection to Magdalen College because of its namesake, it was customary for many years for the Lodge to meet annually for a festival dinner in the College's dining hall.The symbol on the Lodge's badge (as seen at centre top) is that of Magdalen College Tower which was completed in 1509 and is an Oxford landmark.