Cover Page - shares	9 Months Ended
	Mar. 31, 2025	May 02, 2025
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Mar. 31, 2025
Document Fiscal Year Focus	2025
Document Fiscal Period Focus	Q3
Securities Act File Number	001-41827
Trading Symbol	MEIP
Entity Registrant Name	MEI Pharma, Inc.
Entity Tax Identification Number	51-0407811
Entity Central Index Key	0001262104
Current Fiscal Year End Date	--06-30
Entity Filer Category	Non-accelerated Filer
Entity Current Reporting Status	Yes
Entity Emerging Growth Company	false
Entity Shell Company	false
City Area Code	858
Local Phone Number	369-7100
Entity Small Business	true
Title of 12(b) Security	Common Stock, $0.00000002 par value
Security Exchange Name	NASDAQ
Entity Incorporation, State or Country Code	DE
Entity Address, Address Line One	9920 Pacific Heights Blvd
Entity Address, Address Line Two	Suite 150
Entity Address, City or Town	San Diego
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92121
Entity Interactive Data Current	Yes
Entity Common Stock, Shares Outstanding		6,662,857